1950 mercury pressure plate ?

I ordered a 50 merc pressure plate from my local clutch dealer and I think it might be the wrong part.. its a 10 Borg and Beck pp but the bolt holes are only 10 5/8. I believe the bolt pattern should be 11 5/8.. do i have the wrong pp or flywheel?

 

Time to bring the flywheel with you and match it up.

 

I measured the flywheel that is from my '51 and bolt holes for PP are 11 5/8 o.c. Clutch disc was 10" diameter.