RN & Regulatory Numbers

RN, WPL, and CA numbers identify the company behind a label and set a firm earliest-possible production date.

Marker / Feature	Era / Value	Research Detail
No RN or WPL number	Before 1952 Pre-1952	A textile garment carrying a full maker name and address but no RN or WPL number often predates the registration system entirely.
WPL number	1941–1959 1940s–50s	Wool Products Labeling numbers predate the RN system. A WPL number points to a wool-specific registration, generally mid-century.
RN 00101–04086	1952–1959 1950s	The first RN numbers, issued by the FTC between 1952 and 1959. An RN gives a temporal floor — the garment cannot predate the year the number was issued.
RN 13670 and above	After 1959 1960s onward	Numbers above roughly 13670 were issued after 1959. The exact issue year sets the earliest possible production date.
CA Identification Number	Canada All eras	A five-digit code prefixed with 'CA' identifies a Canadian manufacturer or importer — the Canadian parallel to the RN system.
The number dates the company	Caveat All eras	An RN dates the company's registration, not the garment itself. Always cross-reference with construction and fibre evidence.

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