That one would take the later "open style" shifter that kind of resemble the shifters on that PH501. They're easier to find and cheaper than the early ones I have.
I can't guarantee that they'll fit. There's a lot of wierdness when it comes to Peugeot shifter bosses, as Tigerprawn found out.
Tigerprawn--
I bought a pair of those shifters on eBay, so you'll have to find another way to repay me. Send me a titanium-railed B17 and we'll call it even.