curtisports2
No. The P for the Philadelphia US Mint branch was not used on any US coin (except for the 'war' Jefferson nickels of 1942-1945) until 1979, when it appeared on the new SBA dollars. It was added to the nickel, dime, quarter and half dollar in 1980 and is still used today, but has never been used on one cent coins.
The only mint marks found on 1977 quarters are D-Denver and S-San Francisco (found only in proof sets for collectors).
Nancy
No. Most didn't and don't have mint marks. Most coins are minted in Philadelphia, and Philadelphia doesn't use a mint mark.