Not sure if Gerald's details are correct (or incorrect for that matter) but I do know that Esci and DML's BMP-1 and -2 kits were "cut" by the same die-master and that they are very similar kits. However...
The DML BMP-2 is a later production one with the Anti-rad liner. And they also did a afghan version with the spaced armour add-on and small BMP mine plow named as the BMP-2E.
Esci's kits are of the BMP-2 early without the anti-rad liner.
As mentioned, each kit has its own problems, the main one being the "cant" of the rear upper hull troop hatches. On the real deal they are paralell. Also, the shape fo the muzzle is incorrect...it should be square not scalloped. There are also a lot of "issues" with the suspension and tracks. To be honest, to make a completely ACCURATE BMP-2 it would be best to start from scratch.
but who has time?
What can be done? SP Designs BMP-2 upper hull replacement (Early or late), SP Designs or Model point replacement turret, Model point replacement barrel, and many other items if you have the inclination and money.
Also, it has been rumored that Miniarm will be coming out with a full resin BMP-2 kit that we all assume will be hyper accurate, with a hper accurate price too....
Here is a picture of my recently completed DML BMP-2 with SP Designs upper hull, SP Designs turret, and MV Lens. I think it looks good enough, but notice the "scalloped" barrel muzzle.