IMHO, nobody was really able during a DF to distinguish between these subtypes. Afaik, there were even a lot of La5FN-airframes equipped with ASh82F-engine in late 43 and 44, because of production problems wit hthe FN.
The only possibility to find out what type it actually is/was, would have been to check the remains of a crash on the ground.
IMHO, the difference La-5 / LaGG-5 is just different naming. There are even many claims for "LaGG" w/o a number

. Similar can be found for IL-2. In 44, virtually all IL-2's had a reargunner = Heckschütze. Nevertheless, only some claims are "IL-2 m.H." = mit Heckschütze = with rear gunner, although definitely >90% must have had one.