Hey thrila, don't get yourself into too much trouble!
Karnak, I recently bought a small die-cast Mosquito. It's not 100% accurate, but I noticed a couple things about it. It's supposedly an FB.VI, it's got the guns to prove it. But the engine cowlings look different. If you search up Mosquito FB.VI, you get this:

Other Mossies (like my model) have this cowling:

I'm not sure, but it seems like the Canadian produced Mossies have this cowling. I'm assuming only 2-stage supercharged Merlins would need this. Since the oil cooler, cabin heater and rads are in in the inner wings, the intercooler is where the old intake was and the new intake is now that hole under the prop.
In addition some of the Mossies I've seen have only 10 exhaust stubs per engine:
