Hi, well I'm back, was out on Monty today.
http://i268.photobucket.com/albums/jj9/mustpost/mon.jpg
I bought one of the 1st in in the UK in 1976 and ran it for a couple of years, most of the comments here appear to be correct (according to my memory!)I rebuilt it a couple of times, it ran the big end roller bearing and some other interesting things. The Amal levers were just not suitable for robust competition and I replaced mine with nylon ones. Monty is not that machine sadly, but a very genuine bike I bought a couple of years ago - however he does now feature my original bars which somehow survived divorces, house moves etc. I have replaced a number of things (and I know the back box is not genuine) but I still have a pinkish rear guard (the nylon aged over the years - the original colour was cream/translucent). I recently picked up a NOS tank still wrapped in MCNews paper dated 1977, not fitted yet but great to see one unwelded/figlassed etc.
If you're going to keep it for a v long time things to look out for would be exhaust bits, pistons (engine?), unbroken airbox - v rare, original pegs and the old chesnut - an unbent alloy front stay. I know mine is a Sammy Miller one, and I have a sump guard to fit, but I believe in contemporary after market stuff being OK. Good Luck! I obviously have a PDF manual, but I would guess you've found that.