Irwin's is thought to be a GBD second and part of the Oppenheimer Pipe holding company. They were made in England. It is unknown if they were also made in France.

Irwin's Conquest, courtesy Doug Valitchka
Conquest detail, courtesy Doug Valitchka

"The warm dual-tone brown finish deepens with repeated smoking. Finest Rum is used in the special process of maturing these fine pipes. It's smooth flavor complements the natural taste of fine tobacco." -catalog ( 1976 )

Several Catalog pages from a Circa 1950s Oppenheimer Pipes Catalog featured Dr. Plumb's pipes.