There are no cams or cores available for this engine. Unless you can find a usable core, you are SOL.
I believe the cores (i.e., they will physically interchange) for all the Dodge hemis and polys should be the same, though. But the valve timing is very different due to different angles of the lifters in the block.
Whether there is enough meat there to regrind a hemi into a poly (or vise versa), I don't know.
I have a reground cam for what I BELIEVE is a Dodge hemi, but might be a poly. Bought on ebay a long time ago. That's why I can't be 100% sure what it really is. Definitely for the Dodge block, though.
Since it's been reground once already, I cannot be sure if there is enough left to do another regrind or not.