Yes, the OpenRAIL licences are deliberately not open source. Being open source or not is binary, and proprietary is the antithesis of open source.
There are of course additional ways to describe specific proprietary things, like distributable in this case. Distributable but non-free, because the software license is morally judgemental, and limits 'fields of endeavour'.
I'm with you on "not open source", but I don't think "proprietary" works as the opposite of "open source" here.
The dictionary definition of "proprietary" tends towards "one that possesses, owns, or holds exclusive right to something" - that doesn't quite fit here, because models licensed under OpenRAIL aren't exclusively restricted to their owners.
They have terms of how they can used that are more restrictive than open source licenses, but they don't enforce "exclusive" usage by their owners.
Are you saying that because the Open RAIL M license doesn't conform to the OSI definition of "open source"?
I agree that it's not "open source", but I don't think that means it's "proprietary".