Green’s Dictionary of Slang

stamper n.

(UK Und.) a carrier.

[UK]B.E. Dict. Canting Crew n.p.: Stampers [...] Carriers.
[UK]New Canting Dict. [as cit. c.1698].
[UK]Bailey Universal Etym. Eng. Dict. [as cit. c.1698].
[UK]B.M. Carew Life and Adventures.