I’ve not seen anything indicating fleet owned, but I’m fairly knew at this stuff. I just find it strange to be a plate attached versus just a number stamped into existing sheet metal.

1957 Chevy 3200
Daily Driver
PS, A/C, Tilt column, Rebuilt 350, Rebuilt TH350, Reupholstered Bench Seat, sound proof/insulated, LED headlights/taillights/backup lights/interior courtesy lights.
Follow in the DITY