I suspect this has a replacement body. The dash lacks typical holes and stamps.
https://sacramento.craigslist.org/cto/7560053511.html
“BUICK V6, WARN OVERDRIVE, NEW SUPENSION, NEW POWER BRAKES, NEW GAUGES, BOXED FRAME, STEEL BODY-NO RUST. LESS THAN 1000 MILES SINCE RESTORATION. CAN DELIVER WITHIN 100 MILES.”