I am looking for sources now, but my understanding was that the T-55 were all supposed to be in the line to be scrapped as of several years ago, which means there isnt much point in keeping the ammo around. If this is the case, any left over ammo was probably stored in poor conditions.But is there even enough ammo for that sort of thing? There are no line of production for T-55 ammo and any stored ammo must be decades old.
I guess time will tell. It's not like Russia will tell us how many T-55 ammo they have stored so the only way we will know will be via their performance in the battlefield.