I dunno, I see some pretty fine worksmanship there. Thin/smoothed lugs, delicate seatstay top work... I'm thinkin' closer to top o' the line.
Pics of the dropouts might help. I especially like to see the inner face of the right rear DO, to show what they did for chain/freewheel clearance.

Anyway, definitely worth cleaning up, full spa treatment without repainting is what I'd like to see. Not that my opinion counts, not my bike, just mouthing off...

If you don't have any EvapoRust, consider buying a gallon, works like magic.