Can we see some more pics? The lug spot and a shot of the twin dimples with the FD back in place? I think without the FD in place there's some confusion here.

The way the pics appear to me, those two dents occurred when something was clamped to the frame - something with an open end facing backwards, not like on an FD that would have its open end on the non-drive side of the tube.

No other marks, so it also doesn't appear it was anything else (like a bottle carrier or something) that you yourself had mounted on the tube. I think it's highly likely a shop did this with their stand. Shame on them for not pointing it out after they did it, too.

DD