I picked up my wide-body Javron in January (couldn't have been a worse time to drive from UT to MN and back pulling a 20 foot box I built on a 10 foot trailer (welded on a hitch extension, mounted taillights on the back of the box)).. squirrel..
A manual would helpful but is not 'necessary'. The bootleg (they don't allow access to the current one anymore but you probably knew that) Backcountry isn't a bad guide but theirs are not exact Super Cub replicas like the Javron so some things vary - but still good reference.
Seeing pictures on here is great - I wish guys would post more - says the guy that has posted none. But I will - my fuselage is not the one I ordered so I have 80 hours logged but I had to take apart everything that was done (floorboards, brake pedals, seats, etc) so I could weld all the doodads I wanted in. I am just now (almost) back to the starting point and put the cargo floor back in. I think with so many of us building Javron kits along with the project threads already on here, no manual will be fine.
Jays 'hardware kits' are very organized with everything needed for that task in the same little bin and labeled. Most of the parts are pretty easy to identify and figure out where they go but some of the aluminum, if you get the interior can be a head scratcher - I remember Sam (Javron for Dummies) mentioning that too during inventory.
Of course all the posts and pics from the certified guys are awesome. That link (I can't find it now, I suck at searching the site) that Steve Pierce posted on the super screwed up cub was a good example of what not to do - nice that he put comments on each photo explaining what was wrong.
The builder assist is great I am sure - obviously from the posts above.
I think with all the help we have available here no official manual isn't a problem - on the other hand I do wish/hope he makes one some day.