Thanks Russ F and Don A for the info.
After posting my query I found the PX-10 database at: http://www.iag.net/~davidg/PX10.htm
In many of the photos it's hard to tell what crown is used, but the one that I *can* tell is the same as mine is: http://www.iag.net/~davidg/67_PR-10.htm
This PR-10 has painted rear dropouts though, where mine has half-chrome. Mine has different decals too.
The database says "Around 1970, Peugeot began stamping the [serial number] on an aluminum plate which was riveted to the underside of the bottom bracket shell." Mine has the two holes where the plate used to be riveted, so I guess I have a ~70 or a bit later. As Russ says, it's pre-74 as it has the Reynolds decal on the seat tube.
No sign of a seam on the back of the fork blades, so they could be Reynolds. Or the decals could lie - there's a decal that says "Inoxydable" yet this thing is a rustbucket!