The dents are most likely from the deflector hump on the receiver as the cases get thrown into it upon ejection. better that than hot cases in the face. Once you clean deprime and size a couple of cases, see if they chamber without sticking. If they chamber okay, load them up, they will fire form when you shoot them. Of course, if your rifle does the same thing as whatever gun they were originally fired from does, they may get dented again. Unless it actually creases the brass, or happens in the bend at the taper, they're generally reloadable.

If the primers were originally crimped you can try priming a resized case and see if it is difficult to seat. If so, lightly ream the primer pocket's edge with a mouth reamer or pocket reamer to cut the crimp. I reload my M1A exclusively with once fired NATO brass, and have to ream the primer pockets in order to seat them properly.