Hi!
Probably found the info you're after. U-70 seems to have the same "early" pattern of holes as U-96. Same Germaniawerft/Kiel origin, different batch, early VIIC. You can find a neat artwork of her turret's starboard side on U-boot im focus, Edition 3, page 19. Unfortunately i'll be away over the next 4 days, but I'll try to post the picture as soon as am back, just in case you dont get the picture earlier.
Cheers!
SG