Hi Graham,
It just occurred to me that a company by the name of Goff Professional (Florida-based, I think) specialises in Hammonds of all stripes. Their website is:

http://www.goffprof.com/

Hammond used to produce a manual (no pun intended ;-)) covering drawbar registrations and the anatomy thereof but no doubt it's been out of print for many moons. However, Goff are probably worth a shot (who knows what they might have in a dusty corner somewhere). In the UK I don't know where you might locate one - are there any organ enthusiasts' clubs around? Incidentally, I bought my first Hammond, an L102, at Chiswick Organ Studios in 1965 (I guess it's probably made way for a pizza joint or Indian restaurant by now). Anyway, good luck in your efforts.
Best regards,
BR

Me again, Graham.

Cop this.
http://theatreorgans.com/hammond/faq/hammond-faq.html#SEC8

Oh, and Goff are in Connecticut, not Florida like I said at first.

Cheers,
BR

Big Red....Thank you...Links Received.

Graham UK