Hmmm. The frame appears to be a c.1973 PX-10E, with the same steeper angles that the 58cm one I had possessed - makes sense in this smaller frame, though. But '73, '74, lots of PX-10s seem to have had steeper angles.
Someone mentioned the "UO-8" styled cable stop on the chainstay, but I had a couple of PXs with those a few years back, one with Nervex Pros, one with DuBois plain lugs.
The serial number under the BB looks a lot like the funky numbers on the two PX-10s I used to have a few years back - hand-stamped and crude, despite being within the riveted plate period. Maybe Peugeot ran out of plates for a few weeks? David Goerndt at one point thought these sorts of numbers might mark warranty replacement frames. It is odd, though. You have relatively neatly stamped numbers (parallel to the spindle) in the 60s, metal plate numbers from about 1970 to about 1978, then stamped numbers running perpendicular to the spindle starting in 1979, with an added date code starting in 1980. These crude numbers aren't all that uncommon, though.
The fork looks to me like the ones on PR-10s, though, but with different decals. The crown is identical to the ones I'm accustomed to seeing on PR-10s - much too rough for a PX, too crude, etc.
The wheels could be from a UX-10, the short-lived 27-in clincher version of the PX-10 made for the U.S. market - or someone could have just gotten tired of punctures and had new wheels built up on the stock hubs.
My feeling is that someone noticed that PX-10s are bringing more on eBay than they once did, and put together a complete bike out of parts on hand - the Dia-Compe levers and SR bars and cheapo Tourney cranks were what was on hand that would fit, I think.