What kind of single action revolver is more to the point.
Generally, a two-piece gripframe is required for wooden one-piece grips, so the wooden block can be inletted for the mainspring and the front & rear grip straps - with a solid. integral wood connection from side panel to side panel.
The block's exterior is then shaped to the gripmakers taste/style.
Most modern SA revolvers have one-piece gripframes, which is generally a deal breaker - but original and repro blackpowder Colt-clone revolvers generally have two-piece gripframes.
Blackpowder style gripframes can also be installed on some modern SA revolvers, as custom work.
IIRC, alternately, some folks have cemented (epoxy) a right & left grip panel to a central filler block, making (in effect) a one-piece grip for modern, one-piece gripframe SA revolvers - which would have to be destroyed for any mainspring disassembly/repairs.
.