Interesting discussion.  I have noticed over the years with my own
collection where occasionally the exact same arrangement might show 
up on more than one brand.  If this was anything like the phonograph
business, sometimes companies would lease or sell their masters to
other companies.  Thus on recordings, the same exact recording might
show up on Cameo, Grey Gull, Lincoln, Perfect, Bell, Broadway, Banner,
and several others.  Sometimes, they would give the artist a different
name but everything else was the same.  This seems to be true
especially of the "dime store" brands.  Columbia masters were used for
brands such as Standard, United, Harmony, Busy Bee (I think), Arentino,
and many of the Silvertone recordings (Sears) and the later Harmony
(Montgomery Ward).

It would not surprise me that piano roll manufacturers did the same to
some extent.  They sold/leased masters to other companies or they made
the rolls for another company and put the other company's name on the
roll.  I am sure that some of the smaller, tighter bottom line companies
did not have the cash flow, arrangers and or arranging expertise to make
their own rolls from start to finish.  I doubt that it was direct
pirating in most cases.

Randy Hammond