Correct, They could get the scopes in the field (ZF4 or ZF41) but it is doubdfull they could get the scope mounts for the weapon.
According to army tests the MP 43 was good for sniping upto 600m, but according to airforce tests that was only 300 meters and thus optics where deemed not necessary. (please note that the army made this series of weapons, but the airforce tested them also to see if it was better then the FG42, it was not so they did not adopt it at that time)
Snoox, is it funny that you point out one of the positive points according to official airforce tests as a negative one. I will quote a book for this one.