RHS Heads .. Not happy.
I can understand the frustration, but unless its way off, you probably don't have anything to worry about.
I don't see how anyone who could be taken seriously could tell you that the roller will absolutely be right in the middle of the valve on a different set of heads.
Do you have hydraulic lifters or solid? Is it set up with a checking spring or regular valve spring?
Have you run the pattern on it?