Oil pump return gear identification

I have been trying to sort out some pump parts over the last few days and have a question. Having refurbished/reconditioned probably a couple of dozen Norton oil pumps over the years (redominantly from singles, but also some Dominators and Commandos), I thought I had most the answers to these things, but have temporarily stumped myself. I do not at present have a complete Commando pump to resolve this question.

1. A single (ES2, Model 18, Big 4, 16H) pump body has the timing cover outlet at the top as fitted, while the twins have this at the bottom. The twin e.g. Commando pump hence has the return gears at the top of the body. and the single at the bottom.
2. I understood that all the twin oil pumps irrespective of the model, have one of the wide oil return gears intergral with the pump drive spindle.
3. However, I have a couple of pairs of these late model return gears (0.407" wide), each of which one gear of the pairs has the internal drive "tangs" and therefore from the "bottom side" of the pump.

Can somebody please resolve my confusion. I am sure the answer is obvious, just not to me at present.

Geoff

Dont know if this may help or not? Watch from 10:27