Hi Jim.
Correct for your installation is the mechanical pump driven off a lobe on the distributor shaft. My car is a one-off, in that it is an Ausca spider with GTA running gear. As such, when raced, it used the pair of Bendex electric pumps, in back. These were always overkill, as the only need for the pair was when it was REALLY HOT, and vapor lock might be a problem. This never happened
, so when one Bendex finally died, I went to the single Facet. That also works perfectly. The parts book shows the later cars all with the Fispa mechanical pump. As once a race car, the electrical pump has the advantage of STOPPING fuel flow at the flick of a switch, whereas the mechanical continues to pump as long as the engine runs. Also interesting is that in my particular car, the mounts for the electric pump were in place when I purchased the car. You might check under some other '65's and see if they came with the bracket back by the tank as well. Does this help?
Gordon Raymond