Tange dropouts on the fork? Probably not original.

Interesting frame, tho. From the rear end up to the head tube/head lugs it appears to be upper-tier, like a Super or Mexico. But the head lugs are all wrong for either of those models. Decals are late 70s/early 80s Super or Mexico, but of course could have been added at a later date.

Just spitballin' here, but I wonder if it was originally a Super or Mexico that had a header and received a new front end (lugs and head tube, perhaps even top and down tubes) in addition to the fork. Stranger things have been known to happen.

Clover cutout in BB shell, long Campagnolo rear dropouts, short fluted seatstay caps (Sports tended to have long, flat ones), mis-matched fork, paint which appears unoriginal, and a seat lug lacking the window cutouts of the head lugs.

This particular frame seems a mix of Super/Mexico and Sport identification cues, at least to my eye.

Edit: I'll also add that the fork resembles the replacement "Italian-style" forks once available through Bikecology/Bicycle Warehouse catalogs in the late 70s/early 80s. Unfortunately, I'm a couple thousand miles away from my reference library and cannot confirm the details. How about a detail shot of the rear brake bridge?

DD