Nope, they grow, should be fine, what kind of snails? found a petland yesterday thru the net, stopped in cause they have specialty fish and can go handpick the fish you want even if non stocking items. anyways, she gave me a bag of ramshorn snails, I declined because I dont want ramshorns but that I informed her to do some research on these types of forums to see what people pay for ramshorns, needless to say they are not priced items not free, but she is getting me a half dozen decent sized MTS's for my honesty and the fact MTS's are free most places anyways.
But to answer your qesution, NO he will not molt, it grows its shell, It should heal up just fine, maybe a slight seamline but it will heal.