I have no idea, but you are exactly right on one thing, the RE's are much easier to find. I've been looking for a 42RH and not having much luck around here.
I was able to find a package deal on a pair of 42RH’s around here - well, it took a 3 hour road trip one way. I had one of them rebuilt by Dynamic. They also reworked and upped the stall speed on the converter to use behind a stockish 340
