The chance that you have the original 36b computer in your pump is very slim. Computers were only guaranteed for about 20 months and this is about how long they lasted without rebuilding. When the computer quit working, the station owner called a service man, the service man pulled the computer and put in a rebuilt one (a service station could not wait for it to be rebuilt). The old computer was then rebuilt for some later pump. They never were taken back to the original pump. I believe the original 36b computer had a side reading for the total gallons, check yours to see if it was replaced with one that had the very small numbers on the face of one side of the pump.
Author, Gas Pump Identfication books 1st & 2nd Editions & Air Meter Identification books
We rebuild ECO air meters and sell parts.