The body is a 20 gage galvanized 3A shaped body.
https://anchorage.craigslist.org/cto/6104651920.html
“1956 CJ-3B chassis with new 20GA galvanized CJ-3A body. New springs, frame brackets, body brackets, Overhauled1968 Chevy 283 cu. in. V8, 2 bbl Rochester Carb w/manual choke. 1958 Chevy BelAire tail lights, LED headlights, NOS TransDapt adapter, new transmission gears, new transfer case gears, new overdrive.