Many gas brands used a special pump for different eras. Most known is perhaps the connection between Esso and Gilbarco. Also Martin&Schwarts pumps were (almost) always used by Mobil after WWII and onwards into the 50's. There are probably many others... when/if you find a pump that you want to buy, ask here, or just do it in any brand you like. What (I think) is more important is to do the pump in a gas brand of the same era as the pump was manufactured.
Then its he type of gas - premium, regular or a specific names like "Mobilgas", "Good Gulf", "No-nox" etc. these names are connected to certain paint schemes that vary from time to time. Get the book "Gaspump restoration Guide" by Scott Benjamin (available through this site). It shows most known types of gas as well as the paint scheme and color code.
Hope this helps,
Claes
[This message has been edited by fast66 (edited 06-02-2005).]