Other than the bezel itself - it's virtually identical to the pair of oldies I just picked up (mine has an "eyebrow" as part of the bezel whereas yers has an "eyelid" that may even be separate)... and minus the rust ofc lol The faceted reflector is the same, high/low beam is the same as is the switch - but yours may have a plastic lens instead of glass... not a big deal ofc. The nice thing 'bout these is if for some reason you think it inferior - it's easy 'nuff to rewire and replace the bulb.
The one I'm gonna clean up and paint for my build is on the left (it is a lil different as it's got a built-in horn) and TBH I suspect they're not nearly as old as my bike, given the labor involved in cleaning up these freebies - I think yer defo better off just getting the new "vintage" one you found fer twenty bucks heh
(click to view)
Brightness is a simple matter of tryin' different bulbs (the reflectors in these are actually awesome) and for battery life - they sell LED replacement bulbs for flashlights/lamps that'll fit right in there w/o modification.
'Nite-Ize' part# LRB-07-PR:
Nite-Ize LRB-07-PR Bright White Maglite LED Upgrade
I
really like the "eyelid" on yers BTW
edit: heh - I just noticed yers comes w/LEDs FTW! (given the cost of those - it almost pays fer itself lol) So if you want BRIGHT I'd replace just the "high beam" with one of the crazy super-bright bulbs they sell fer Mag Lights... sorry, no part # to pass on to ya as I've not done it yet