DixieDarlin,
You have a wonderful family heirloom and it's monetary value is irrelevant in my opinion. The value is in handing it down thru future generations with some notes of everything you know about it.
You mentioned it doesn't have 5 screws. That's because it's such an early model, that the design for the screw in front of the trigger guard had not been incorporated into that model yet. So it's still a four screw design.
It is a quality made, turn of the century revolver very well engineered, assembled with skilled craftsmanship’ and hand fitting no longer affordable on a competitive market basis, and that we'll never see again, ever.
Shoot it to your hearts delight, and it will delight you with its fine accuracy, and comfortable recoil.
Simply put, the only usual issue with these marvels of yesteryear is they are gummed up and dirty. Old oils of its time do not match the science of today or the quality of these old guns, and actually dry up and harden to the point of impeding operation and accelerating wear. The simple solution does not need a gunsmith. Just one of a few premium modern gun products from any sporting goods, gun store or hardware store.
Most are both cleaning and preserving agents; Breakfree, Kroil & M-pro7 are some of the best, but there are others. Disassembly is not necessary. With a spray can version of the product, flood and flush the revolver thru every opening and crevice until the black gunk stops flowing out, let it drain for an hour and wipe it down good.
Definitely with grips off: Loosen the grip screw completely and carefully push down on the screw head until the bottom grip separates, then remove. Now push the top side grip off with a finger or toothbrush from the backside thru the grip frame. Scrub barrel bore and cylinder chambers with a simple cleaning rod kit found at the same places as the cleaning agents above, and patches cut from rags is all you really need. And scrub any observed exterior and crevice crud with an old toothbrush with bristles cut off short for stiffness.
For rust spots, use Bronze wool, not steel wool, size 0000 and toothbrush with bristles cut short, and a rust removing agent/gun cleaner like M-Pro 7 (odor free), Kroil or Breakfree and gentle scrubbing.
Rust pitting must have all red color removed to arrest it's cancerous growth (use 5x glasses or stronger to see progress). Then re-oil or wax over.
Once cleaned and lubricated, with a few simple checks you can determine if it’s safe to use. Cock the hammer slowly and confirm the cylinder is locked in position for each of the 6 chambers. If satisfactory, now operate the gun by pulling the trigger slowly until the hammer drops. Again, confirm each time after cycling the action, that the cyl is still locked in position. Cock the hammer in single action mode. Gently push on the hammer to confirm that it will not drop w/o pulling the trigger.
Here' another section of this forum for posting photos of the other guns that members can advise you on:
Firearms & Knives - Other Brands
Enjoy your heirloom!