At the point of terminal frustration, I imported the JPG of the revolver into Blender and cut out the shape of the grip and trigger guard like taking scissors to a magazine. Whatever. A win's a win.
I took another crack at making the grip of the gun, this time drawing a shape with vertices which would then be, in theory, filled in to make a polygon:
It seemed to be working until I realized I'd somehow managed to make it a 3D shape instead of a 2D outline: