So what is the difference in the thrust plates?

Jim Carter lists a thrust plate for the Chevy, but its only one part "Camshaft Thrust Plate Chevrolet 1937-1962".

Right next to it they list a GMC part, with the thrust plate and the spacer "Cameshaft Thrust Plate GMC 1939-1959". Going by what I had on the motor, I got the one piece chevy part.

So I need the part they list as 'GMC'?

Do local auto parts have this? I'm gonna get nailed $10 to ship a $12 part frown