Everybody made Gulf pumps. All of the major manufacturers during the 1930s-1970s built pumps with custom cabinets for Gulf, all very similar in design. Bennett, Tokheim, Wayne, Southwest, Erie, even a couple of Gilbarco designs, early on in the program. Gulf had its own rebuild shop (Atlanta) and would combined functional parts with cabinet parts, even ordering re-skin kits and modernizing pumps. Common practice with most majors and many pump rebuilders including Universel, Cherokee, and others. I've worked on a rebuilt pump with a Gilbarco pumping unit, Tokheim meter and air eliminator, and generic Veeder Root reset and switching. Known in the industry as "Frankenpumps" for their put-together design.
Southwest lasted into the early 1990s (I was a distributor) before selling out to Schlumberger. Schlumberger sold its pump line out to Tokheim, which has, of course, sold out to Wayne. I sourced a meter for a late Southwest electronic pump just last week.
Wayne Henderson