As noted by bertinjim, JPR was the son of Jo Routens. Many of his frames apparently were built out of house and labelled Routens. Some think that even after JPR took over his father's business, that the early frames were still being built by him (JR) though they were badged "Routens". This frame post-dates JR's death.
Many "Routens" frames seem to have been of good quality, but, I don't think, after his father's death, they would be regarded up to the level of his father's reputation (who is often mentioned in the same sentence as Singer and Herse). I would think that if it is filet brazed (JR's signature method) this frame would be considered among the best JPR produced and may not be a contract frame. I have never seen a photo of JPR frame that was filet brazed, they all have had lugs.
Judging from the photo I can't tell whether it is filet brazed or not, but I do think it likely to be one of the better JPR bikes. $425 is a good price and may be a bargain. I wouldn't be surprised if it is worth 2-3 times that.
Hope this helps.
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