20 years ago I replaced my 72 P-Bass neck with a Schecter-neck because I messed up the original neck trying to swim on the fretless wave...?!?! Anyway, it is still a good bass with the Schecter neck, but I like to go back original. Where do I find original Fender necks with the logo an everything?
eBay.. be prepared for the prices, though.. a 1972 neck is going to cost alot.. is your neck salvageable?? it would be cheaper to have a new fretboard installed on the original neck, than to buy another used Fender neck.. other than that, you'd have to find a newer replacement, and get a logo for it.. warmoth, WD and AllParts have replacement necks, but all are branded "LIC. By FENDER" on the heel.. also, you'd have to find period correct tuners.. and that's gonna cost also.. unless you already have them..
It'll never be original without the original neck. If you can put a new fretboard on it, I think that would be the best for value to have serial numbers matching.