What to look for in a used flintlock?

[Mr. 16 gauge]

I was playing around on line the other night and found a local gunshop that has a .50 cal CVA Hawken flintlock for sale. The gun is used & has a bare bones look about about it (no patch box, ect)....the asking price is $159.00

....I've been thinking about a flintlock rifle; kinda wanted a Pennsylvania long rifle, but this may do. I know I need to check the bore, but what else should I be checking on a used flintlock to make sure it is in good working order?

Thanks in advance.........