I am aware that there was an error on a paticular dime where they left the mint mark off on a philly dime but I can't remember what year? I wanna say 1980 but I really could use the help of someone else! Thank you
I looked at www.PCGS.com, and they list a few proof set years of no-mintmark dimes in the price guide section of proof sets. Looks like the 1983 no S might be the one that you're thinking of.
No I am sure it was a P mintmark The first year they started putting the P mintmark on the dime some got out without the P
Actually I just looked on E-Bay and it was the 1982 dime that was missing the P mintmark You were right thank you