Jeff,

according to OS they are. Each engine is run and the pump is tuned to the engine and then "sealed" prior to sale. But I have no clue if this is in fact true.

I disassembled my used Hanno's pump because the previous owner decided to use some gunk instead of gaskets to seal the engine backplate... Unfortunately, as we know, the Hanno 2 nipple pump is different from the SF-P's and RF-P's. As far as I know there is no difference between these two engines other than the crankcase and piston sleeve. Maybe the pistons are different due to the skirts. The pumps should be identical as Will points out.

David.