1903 stock stamp question "J F"

I recently acquired a Remington 1903 with a scant stock. The stock is marked on the left side with RA-P and JF. I know that the RA-P is a Raritan Arsenal rebuild stamp. Does anyone know what the JF stamp is? I have done an internet search which showed that there are a few rifles out there with this JF stamp, but none of them indicates what it means. Box around RA-P is about 1" x 3/8", letters are 1/8" high. JF is in 3/8" high letters.