It doesnt have a mint mark. But appears to be silver. I dont see copper on the edge either.i took several pics ,but none really show the color difference but side by side with a 1964 i dont see difference. The weigh is correct for a 72.
Maybe it's just in good shape and you can't see the copper? A quick test is to take your 64 and listen to the sound it makes when you clink it against another silver coin. Then take your 72 and clink it against that same silver coin. If the 72 is clad it will make a higher noise.
Yikes! Don't ever clink a coin you may think is valuable against another coin! As for it being in "good shape"? A 1972 Kennedy thats in good shape will have an edge as bright as a shiny new cent since the Clad Kennedy's had 100% Copper Cores. I would more expect that the coin was silver plated since silver plating will NOT add a whole lot of weight to the coin. I would recommend that the OP post pictures and/or send the coin to CONECA for attribution.
Sorry! My knowledge extends as far as junk silver so I guess that's not very good advice from a collector standpoint.
