I have the following 1 cent pieces, none of which have a mint mark. If i have 12 they must be pretty common i assume. 2x1960 2x1964 2x1966 2x1967 4x1968 attached is one as an example
Yes, very common. No mint mark simply means they are from the Philadelphia mint. Most years more common than the mint marked coins.
The only year for a Philadelphia Minted Cent with a P Mint Mark is the 2017 P https://coinweek.com/us-mint-news/philadelphia-mint-quietly-releases-2017-p-lincoln-cent/ Quote - "The 2017-P Lincoln cent was minted in recognition of the Mint’s 225th anniversary on April 2. The addition of the “P” mintmark was an idea suggested by employees of the Philadelphia Mint. The coin was intentionally released without fanfare to gauge how long it would take before the public questioned the Mint about the authenticity of the novel 2017-P pennies." Closed quote
But, like the English language there are exceptions. Lincoln cents dated 1974 through 1986 with no mintmark could be struck at West Point as well. (Quarters struck 1977-79 without mintmarks may also be a product of West Point.) Then there are the 1965-67 coins of all denominations with no mintmarks which were struck at all three mints.
