Watermans Pentagon Ink Bottle

I recently purchased this Waterman's Pentagon shape ink bottle from a antique dealer in Neepawa Manitoba. I love the shape and I could imagine when it was used as the ink got used up within the bottle you could still dip your nib into get the ink by laying it on to it's side. It measures 3" in height with a 1.1/2" opening at the top. Embossed stamp on the base is Made in USA. Waterman. JX. REG. PFOP. I was hoping someone on the forum could know the date of this ink bottle.