Are they aluminum castings? By the way, you'll need to be much more specific regarding what you have. Dove had the ability to mix-'n'-match intake and exhaust runners and combustion chambers so 'medium-riser-castings' is way too vague. What sort of valve pockets?
They may be just fine and perhaps not so much. At one time, Dove had a whole bunch of castings he'd scrapped, stolen. They were then found on the market and many people were disappointed.
Tell us more.
KS