here's my addition: it's a BJ of another color, a Merlin from sometime in the '70s (I haven't asked or paid for the info from BJ).
Serial number is 15305 followed by a symbol that looks like a club (or 4-leafed clover) with no stem on the BB (and same number without the symbol on the steerer).
This is all 531, has semi-wrap stays and chrome Prugnat headlugs, chrome Zeus DOs and forkends. Repainted and decalled to match original, but lost some of the chrome on the stays. Came with braze-ons for Centerpull brake at rear, top of BB cable guides but that's all the braze-ons...made for 27" wheels. A very smooth rider!

Oh and BTW...I have additional pics in the photobucket album, and...
it's for sale!