How do I get in to a locked roll top desk? One key/lock opens the roll top and the pedestal drawers.

Excuse first timer. Roll top desk is victorian. Maker is unknown. With roll top down and locked, a piece of paper will slide under the roll top all the way across the writing table of the desk. Someone suggested unscrewing the desk top from the drawer pedestals. I think the writing table will still be attached to the roll top and the roll top will still be locked. Key is inside the locked roll top. What about drilling out the lock?

most of these use fairly standard keys, have you looked for keys at dealers or even online.
also to prevent damage if this is valued, merely call a locksmith to open the lock