If you ever need to remove certain Ovation preamps, you might find yourself scratching your head as you look for the fixings/mountings. The first time I encountered one, it took a little thought so I'll pop this quick tip up in case it helps others.
The OP-24 preamps actually hide their screws underneath a stuck-on plastic sheet with the control legend printed on it.
Get a sharp knife and run it along the edges of the front panel, inside the bezel.
You should be able to pry up the left and right ends to reveal two screws either side. Be careful not the ‘fold’ or kink the plastic as you remove the screws.
Do what you gotta do and, after reinstalling, the panel cover will stick back down itself if you’re lucky, or might need a little contact adhesive if you’re not.