A couple of years back when I was riding PX-10s a lot, I heeded Brother Sheldon's advice. Not too hard for me to do so, actually, as every pair of AVA bars I've owned, with only one exception, was bent, with that droopy effect happening that led me to conclude it was but a matter of time before they failed.
If memory serves me right, the PX-10LE came with an ATAX stem with allen-key fittings. By 1975, when the paint scheme changed (don't have my references handy anymore), I want to say that Peugeot was using better stems and bars for the PX and the PY bikes.
I never had any problems with Pivo stems of any stripe; some of those had shapes similar enough (at a glance) to look period. Pivo bars were always nice, too. I often cheated and just used slightly later Atax and Philippe products.
Russ Fitzgerald, whose only remaining Peugeot is an old AE-18, in Greenwood, SC velocio@earthlink.net