Cool, guys, nice to see M416 and other trailers getting a new life. I have both an M416 and a Bantam T3-C and did a slew of research on parts, etc.
You can find out a lot of what others have done at
Steel Soldiers and there's a lot of solid info on trailers at
Vintage Military Trucks, Trailers. There's also a place in eastern PA, I think it is, who imports a lot of parts from the Philippines for these trailers, like back gussets where the tailgate goes, floor panels in original config, etc. Can't find the link right now, but will search for it if you don't know about them already. He and his wife are very knowledgeable about these trailers, which years had what, what is commonly done to correct bad mods, etc.
Mine are both for sale right now in the Trailers section of the Overland Buy Sell Trade section of the forum:
M416 and the
Bantam T3-C, if you know anyone who might be interested.
Good luck with yours, guys!