Telling The Difference Between Proof Edges

Yes the 77 is a business strike, but not a normal one. It looks NOTHING like a regular 1977 p. I'm saying it is A POSSIBLE 1977 D business strike with no mint mark. The proof in question is NOT PICTURED.

That is to be expected for 35 year old circulated coins, the right one is dirtier and more worn than the one on the left. The head is the same size and it is perfectly normal for the coin to not have a mintmark, that just means it was minted in Philadelphia(no P mintmark on dimes until 1980).

Another thing that affects the apparent size of the devices is die wear. It is hard to tell on such well circulated coins but early and late die state coins do look different so two coins from different die that have seen different circulation should not be expected to look identical. A no D Denver coin would have been produced by a struck through event, with grease filling the mint mark. In that case there would usually be a vestigial mark that could be seen under proper lighting and magnification. Since these coins are from a year where no P mint mark was used, there would be no way to tell a coin struck in Denver using a Philadelphia die from one struck in Philadelphia so the notion of a truly no D Denver strike is sort of meaningless.

Thank you guys very much , I have loads to learn about rosies !