Need Help with Desk Identification

by Ann

I am helping a friend with research on an old mahogany roll top desk he has recently acquired. We are trying to find the maker of the desk and the year in which it was made. The desk has no manufacturer label or mark but we have found a few numbers on the desk: the stamp number on the desk and back of the roll is B27251, the stamp on the back of the lock is CBX1, and the castors are marked "victor, 3, pat jan 16, 1894." The locking mechanism seems to be very unusual. We would appreciate any help you can give us!