The PS proofmark LIKELY indicates a pre 1900 build date-one could (and, can) still get PS proofing, but, PT came along in 1900 and the very great majority of guns built after 1900 are, indeed, proofed for French powder T.
That barrel maker was no slouch, either. The very great majority of Bernard barreled guns I've seen were Paris proofed. Would be good if we can see the flats in a photo. Sounds like a nice gun.
Best,
Ted