I can't post images yet but a little more digging and some more careful attention to the bike's details suggests it's actually a French-made after all (I overlooked the "Made in France" sticker assuming they all bore that title--turns out not to be so). In 1980 it appears identical to the PF10 except for:

Peugeot 103 "course" frame with stamped, not forged, rear drops
"Peugeot" branded rear simplex derailleur
Monochrome fork

That suggests to me that it's a French-issue imported PH10, which is pretty exciting.

It looks almost all original except the chain (obvs), the hub has been replaced with a shimano, it has a new seat and the pedals have been switched out for some japanese clipless (they're old and very battered and need replacement). The paintjob on the frame also needs some attention, which is sad because in general it's great but there are some spots where either someone was trying to drill through the tubes or had it smashing against something routinely for years.

Not a bad find for under $200 USD for everything I needed to get it back on the road. Might have been able to find it cheaper if I had specifically been looking, but this was local and an unexpected find.