I don't see any reason why the La-7 would be a perk plane. It's pretty obvious that a lot of people don't know a heck of a lot about it.
It's not some ultra-late war uberplane that turned up in small numbers in 1945. It's a standard mid-1944 aircraft of similar overall competitiveness (I feel, though we won't know until it turns up) as the P-51D, Niki, etc.
And the La-7 isn't to the La-5FN what the Tempest is to the Typhoon.
For one thing, the La-7 HAS THE SAME ENGINE as the La-5FN.
Don't get me wrong, the La-7 will be a much more capable arena aircraft than the La-5FN, largely due to the extra gun, but it's an incremental evolution of the La-5FN, not a revolution in the design series.
They took an La-5FN and squeezed out 10-15 mph or so more speed with aerodynamic improvements and slapped an extra gun on. I don't see that making the La-5FN we currently have a perkable uberplane.
The skies of AH aren't exactly filled with La-5FNs now, and I don't think you'll see any more La-7s than you see P-51Ds or Nikis or DHogs or Spit IXs now.