Leslie serial number lookup.
Pick the model group from your nameplate, then enter the serial number. Model-first matters: Leslie used different number sequences for different model lines.
Good to know
Where do I find the serial number?
Serial number on the amplifier chassis inside the cabinet.
Why a range, not an exact date?
Hammond serials were issued in production blocks and the tables are built from owner registrations verified against date codes — the honest output is a block with a confidence level.