It was the A-20B I was thinking about, and definetley different provisions.
Those images are wrong.
Here's a little background. A little long but it all ties back at the bottom.
The DB-7 was a French bomber. This was the first variant made, because at the time the US was isolationist. Hence the DB designation ("Douglas Bomber") rather than the later US Army designation A-20. Some months after the French order the Army got in on the deal as well and the designation A-20 was assigned to it. For the first 2 years of service it had dual designations. The DB-7 used 1100hp engines and the second order the French placed upped this to 1200hp engines. The DB-7A upped this to 1600hp engines, same as being used in the Army variant, the A-20A. It was a seamless change. The French ordered more and more and more DB-7s, but only some 70 or so were shipped. Not even all of those were uncrated and assembled before the French invasion. The remainder of the order was diverted to Great Britain. They also took over some Belgian DB-7s as Belgium capitulated.
The Brits, interested in the airframe, requested their own version, with changes to the internal systems and instrumentation (as they seemed to stipulate in a lot of their orders, no doubt for logistics with fuel systems and hydraulics, etc).
The Belgium shipment was underpowered and used as trainers. These were designated Boston I's. The French shipment was re-packed with British gear and guns because it had more horsepower (I assume the 1200hp engines). These were Boston II's.
The name Havoc was ultimately given during the BoB to Boston II's which was armed with 4x .303s and sent out as a night fighter. Yes, night fighter with .303s. It happened a lot, actually. That is how the later marks got the "Havoc" designation.
Back to day bombers, though: The Brits had already heard of the French DB-7A order and on paper it looked good. They ordered their own set, but with British instruments and internal equipment as I mentioned. This became the DB-7B. By the time any from this order had been delivered, the Brits had already given the other planes the name Boston I and Boston II, so this became their Boston III. The first Boston IIIs arrived in England in late August 1941. The first squadron to recieve them wasn't operational with them until the end of that year.
On the US Army side:
The initial A-20 run for the Army wasn't very useful. Many were converted to night fighters. Many more converted to recon planes. Then came the A-20A. The main change was ditching a failed turbosupercharger and going with the same engine as on the DB-7A (1200hp). Armament was 4x .30cal in the nose, and one tunnel gun and one dorsal gun firing aft. Bomb load was only 1100 lbs and range was only 650mi. That's not much more range than spitfire1s and 109Es. The initial order was for about 150 planes.
The A-20B was really an experimental testbed for turrets, but those were scrapped and it went back to basically an A-20A layout (not quite, more on this below), except with 2x .50cal in the nose, and 1 .50cal for the rear gunner. The engines were bumped up to 1600hp. This plane could carry aux fuel tanks to extend ferry range. Previous planes had such short range as to require being shipped to most places and assembled rather than ferried, so perhaps it was to reduce this problem. Because this was actually based more on the DB-7A design than the A-20A, for unknown reasons the fuel tanks weren't self sealing and the armor protection plates were greatly reduced. Perhaps tons of surplus left over from the cancelled French orders? Of the 1000 A-20Bs ordered, under 700 were made and almost all of those were unceremoniously dumped on the Soviets for Lend-Lease. It was felt to be inferior to the A-20A. The Army didn't want it.
With the A-20C, the British and US variants finally reached equality. It had self sealing tanks, additional armor, and the same 1600hp engines. A few mph slower than the A-20B, but with .30cal in the nose. Under 1000 were made. In british service the A-20C was given the same designation Boston III or IIIa (which differed only in electrical systems)
So, as you can see there are 2 main facts to take from this: The Brit variant is really the DB-7B. The A-20C is exactly the same as the DB-7B. Therefore our British Boston III is exactly the same as the A-20C. Same plane. Same specs. Second to take from this is that the Boston in-game is really a mid-war plane which became more common only after 1942. Its top speed of 350mph precludes it from being used in any early war substitution setups or scenarios due to its top speed being faster than most early war planes can go on WEP.
P.S. Interesting fact: The A-20G is actually slower than the Boston III because of all the increases in weight. It more than made up for the loss in speed with overall capability, but most folks in this game probably wouldn't think about it being slower by some 15-20mph or so.
