Why would it matter?
I think he has an "LA" block myself. But if it is a Magnum block, it would be a roller set up anyway. Is there a benifit to doing this if it is all ready a roller block?
The Magnum rocker arms are lubed via the oil galley in the block. The oil pressure makes it's way through the lifter, into the hollow pushrod, and out to the rocker.
This is why you can't easily put LA heads on a Magnum block except for early production Magnum blocks which had the oil passage drilled in the deck surface.