1968 S Nickel Question

Found in circulation today a 1968 S nickel. The coin is pretty shiny still, much more than one would expect from a 1968 coin in circulation. It does have some wear as there are no discernible steps on the reverse.

My question, how does one tell if this is a proof coin taken from a proof set vs a regular coin destined for circulation?

Sidenote, there is a little " Cud" (maybe wrong word?), a small, apostrophe shaped piece of metal sticking up near the necktie on the obverse, running at an angle of 2 to 8 o'clock. It does not appear to be part of the design as it is not connected to the tie or collar. Anyone familiar with something like this on this coin?

I know, picture would help. I'll see what I can do, although not my expertise.

Thanks!