The first Bassman (1952-53): a single-15 tweed box with two pointer knobs and a bottom-mounted chassis.
Marks that can be entered for this maker: Serial number (plate), Tube chart sticker, Transformer code, Speaker code, Pot code, Chassis stamp, Circuit code.
Nothing predates 1951; components only push the date later.
Sold-price aggregates are not collected yet, so the archive gives no figure — condition, originality of the transformers and a documented recap move this model more than any list price.
Evidence: Blue Book of Guitar Values — fender · Internet Archive (Wayback Machine) — snapshot of www.ampwares.com