I think of a thumbprint as being internal, but the par 5 1st hole at Four Streams MD (Smyers) is sort of like what you're describing, if I understand. Haven't been there in awhile, but as I recall it, the green is oblong and set at an angle to the approach. Picture a slice of rye bread oriented with long dimension running from about 7:30 to 1:30 on the clock face. There's a false front, picture a bite out of the bread slice that runs from about 3:00 to 6:00. Could be considered a thumbprint I suppose. I don't recall it ever being pinned in the thumbprint, usually up behind the false front. It might have been possible to leave an approach short left on the front of the green and have a putt down through the false front and then back up the other side, but I don't recall that happening often. There were pin locations where it was not hard for putts to run back down into the thumbprint from up top. That I clearly recall!