I have the following paper on the back of my RM40s:

Someone asked me if these are MLS cabinets. Are they?
Thank you.
Hi Bob,
The paper on the back won't tell you anything since Brian uses it on all the cabinets.
If they are Rosewood, Ebony, or Piano Black they are likely MLS. If they are Light Oak, Dark Oak Dark Oak, or Cherry, they are likely Bud Bailey.
I say likely, because there are some Piano Black from Bud Bailey also.
Walnut, Maple, and Birch, could also be "either" but if they are older, then it could be another cabinet maker.
Brian would be the ultimate authority (obviously) and there may be other variations and crossovers, since finding good cabinet makers is always a problem for smaller manufacturers.