OK, I'm sorry, I had the story backwards, I thought the myth was that it stood for "Roundtable" and that the fact was "Richards".I thought RMC meant Roundtable of Musical Craftsmen
From the Martin Story Site
“ In 1961, Paul Richards formed the Richards Music Corporation, by merging Martin, Blessing and Reynolds,
(In this periode Martins carry a the RMC marking, which officially stands for Roundtable of musical Craftsmen, NOT (officially) for Richards Music Corporation) “
As a division of Richards Music, Reynolds became part of the “Roundtable of Musical Craftsmen” (RMC) along with the Martin Band Instrument Co., E.K. Blessing and Flat/Jacks Drums (all owned by Richards Music Corporation). Instruments produced by these companies during the Richards era all bear a RMC shield logo.
I came across some Martin instruments in the Holton Factory Reference Collection. Several are unmarked, and most are believed to be prototypes. A couple are marked "RMC" for Roundtable of Musical Craftsmen, though commonly known for the Richards Music Corporation.