It will be all paint, my neighbor has a MIL STD pub from back in the day and the paint is the correct OD green for the period... not to mention, it's really, really hard to screw up what's basically flat green
. Being very careful with the prep and using self etching primer as the base with filler primer over that where needed.
Unfortunately it won't be a 40's Huffman frame, that'll be what I believe is a CWC frame (got it cheap) but the lines look pretty much the same. Thus far the possible biggest expenditure will be a truss rod set up from Al Berger (Bergerwerke Bikes), but that's dependent on how what I currently have on hand looks after paint.
I got a correct five drop skiptooth sprocket from Ralph (AS Boltnut), but I also found a Wald non skiptooth with the same pattern (five drop), rusty and cheap (being blasted). So the plan is to set up two drive trains and wheels, one ST, one standard... if I get low balled trying to sell it guess which is going on it?!
It won't be a direct clone but I think unless your one of the obsessive types that knows serial numbers and every little detail (I guess kind'a like those Porsche purist?) you probably won't see a difference. What I very quickly discovered is anything that's actually of G519 lineage has serious $$$ being asked... Except for the Torrington OD bars!?
Side note, my buddy's wife chairs the local Veterans Boat Parade here in our little beach hamlet. This year we honor the US Army, so this should be a pretty big showing. It was originally just gonna be a theme build but very quickly became a "Build it as close as possible", to an actual G519 bike.