Thank you for the link Duzell. I ordered two of the correct pins for less than $11.00 after shipping.
For clarification, I don't have any issues with the BrassStacker mount. It wors great when fitted according to their instructions. I'm just not that enamored with having a long-eye-relief scope. I'm getting a dedicated target rifle to scope in the more conventional way in the near future and figured I'd rather have the Mosin back in Original Condition (well minus some polishing and sanding of certain parts, of course) for plinking and historical interest.