If the shop is even halfway honest they'd stop and call you when they noticed a problem like that. Assuming they noticed it at all. A crack would probably show up as a black line amidst the even grey of the blasted finish. I really doubt there are any structural problems with that frame but you could ask them to keep an eye out. There's no such thing as being too careful or too observant.

I'm good with French, Japanese, and American bikes but I don't really know anything specific about Italian stuff. I can say, however, that if the brakes are nutted it's probably 1970s/early-'80s and if they're recessed-mount it's probably later '80s.