Hello Dave,
you are absolutely right. The part number for the plug-in board connector is SAMTEC TFM-150-02-S-D-A.

But please be aware of the following:
Actually the part used on the PCIeV4BASE / PCIS3BASE card is from SELTRONICS with part number PL124-P-100-G. As we had some minor trouble with the Seltronics counterparts used on the first PIB64IO plug-in boards, we decided to do a revision of the plug-in board and use the SAMTEC connector instead. The numbering of the connectors from Seltronics and Samtec is different. The pin assignment tables given in documentation for PCIeV4BASE / PCIS3BASE are for the SELTRONICS connectors and have to be adapted in your design.

Greetings,