I did a complete restoration of a 51 M-38 about 2 years ago. The owner was able to find all the parts through military suppliers around the country. Fortunately all of the charging system components were good. Parts were expensive but relative to other old cars & trucks, not so bad.
If it works fine, drive it and enjoy it. If at some point the charging system dies, it's not a major deal to convert to a 12 volt alternator, ignition system, etc.
Fred


1956 3100 Pickup/Red/350/3sp OD/PS/Disc Brakes
1957 Bel Air Sport Coupe/Red/355/TH350/PS/Disc Brakes
2017 Silverado LT Single Cab SB/Black/5.3/6 Speed Trans
1947 Willys CJ2A w/F-Head engine