Is there supposed to be a gasket between oil pump and mounting surface?

No they are two machined surfaces that use no gasket.

However, per "How to Build a BBC Engines" it says to use a non-hardening sealer, not RTV! This is exactly what I did and no problems. Wipe off any excess sealer when nut is torqued down! graemlins/thumbsup.gif

If you use any kind of sealer make sure it is just paper thin otherwise the stuff will end up through your oiling system with the oil.

No gasket & no reason to use sealer here.
If the surfaces are flat (you did check right) they seal just fine.
I always flat sand both the pump flange & the mounting surface on the cap. (yes, you need to pull the pins)
If it ain't flat no sealer I know of will work with 200+ degree oil at 60 lbs or so ;)

Thanks everyone, I didnt remember taking a gasket out when I disassembled the engine last summer and didnt find a new gasket in the gasket set so I figured ther wasnt one but wanted to be sure.