I am getting ready to put some old, not so old (vintage?) fabric on the board to sell. My question is, should I wash and press it first? Any help would be apprediated.

Yes

Some like fabric pre-washed, some do not.. my advice is to just be sure and post it pre-washed or not pre-washed so those folks know.

If it is super wrinkled, I would press it. It will show better.

I would press it but not wash it unless it really needed washing. Some don't like it pre-washed, or you never know if someone has allergies and uses a different detergent. Leave it up to the buyer as far as the washing goes.