I was told this several times. This is why I’m sure they did.
I can not find any difference worth mentioning. Save some things like the aluminum rockers ether with the CraneCams written on it or the typical MP stallings to say it’s their own.
I’ll modify what I said to “Crane made ductile rockers,” of which I know stock mechanical rockers were one and I haven’t seen them by anyone else for a long time if ever that I can currently remember. Often, MP would have Crane products with their part numbers on them as you know.
We have a member here, that worked for S&S Cycle (Dusted/DusTed, something like that,) and knew what Cranes offerings were by heart and urged me to get the rockers. (Sadly I did not.)
Crane also made other manufacturers performance parts throughout the years. When Crane parts dried up, so did many of the MP parts.