Your revolver was made sometime between 1882 and 1896, but to nail it down past that, we'd need to be able to accurately determine which model it is, which might take pictures. "WG" means "Webley-Green", after the manufacturers (Webley) and the fellow that designed the stirrup-style top-latch locking mechanism (Green), but some references also say that this means "Webley Government", because so many of them were bought by the UK for training purposes. Does the grip have a flat bottom or is it a rounded "bird's-head" grip? What are the sights like? What do the cylinder flutes look like, are they rounded or do they have a pointed end? Is the firing-pin part of the hammer, or is it a separate piece held in the frame? The ammunition these use is pretty well obsolete by now, but it is obtainable for a price; it's normally called "455 Revolver", but Colt also chambered some of its revolvers for this round, so you can see it also called "455 Colt" (this is NOT the "45 Colt" that you'd normally see in the western-styled Colt SAA); it's a short revolver cartridge with a flat protruding rim, so the automatic ejector can throw the empty cases out of the cylinder when the revolver is opened. If it's in reasonable condition, and you can determine the proper model, it may be worth more to a collector than to a shooter, simply because the ammunition is hard to find.