Not only is the "Oriental" pattern quite scarce (how often do ya' see them, relative to Sheratons, Vines, etc), but the model number offers additional scarcity.
Waterman introduced the lever filler just about a year before switching its numbering system in 1917. The "4" indicates silver overlay. The 12 1/2 PSF (Pocket Self Filler) for a slender pen with #2 nib. Compared to pens starting a year later, the PSF pens have flared barrel threads. All told, a most uncommon pen.
Dunno what I'll do with this one. For now, I'm enjoying owning it. Andy Beliveau did great work on it.
regards
David