Not All Small Block Oil Pump Drives the Same?

[Dibbons]

I mistakenly purchased two oil pumps drive for a 340 I am currently rebuilding. After examining them side to side I found the gear end is slightly different. One has a gear teeth that measures about 16 mm (.630") high/thick (green paint splash in photo) and the other measures only 14.5 mm (.570") high/thick but does have a "step" machined in to make up the difference (photo right). Does anyone have a factory oil pump drive on hand to find which is factory correct? (probably won't make a difference but I am curious about the discrepancy). Thank you. (also posted on FAB)

 

[Cranky]

Is the gear diameter the same? How deep is the distributor drive slot? Should be ok so long as the distributor sits all the way down if everything else is ok.