For what it's worth, Rock Island Auction sold one in very very similar configuration for $5,500 a couple years ago.

Also a Smith & Wesson 44 Russian Double Action First Model, engraved, gold plated cylinder / hammer / trigger, pearl grips, only 77 serial numbers away (7022 instead of 7099), shipped also to "M W Robinson Co., 79 Chambers St. New York City" in a 100 gun batch on the same date of October 18, 1882.

Engraved & Nickel & Gold Plated Smith & Wesson .44 D.A. Revolver | Rock Island Auction

So very likely two guns in the 100-gun same shipment (Oct 18th, 1882 to MW Robinson, specifically guns 7000-7099), engraved / gold plated by either MW Robinson or their distributor in latin america








My guess is OP's is a lower "grade" of engraving if that makes sense, you can see very similar engraving motifs (such as the star burst around the hinge pin; floral swirl around the hammer axis pin), but with just less details and embellishments.
For instance, the Rock Island Auction one had the pearl grips carved into a steer's head, while OP's just looks like ordinary 100+ year old pearl grips



Quite an incredible find that two guns made 142 years ago with the same post-factory gold plate embellishment and engraving can be documented to the same distributor, same ship date, and likely same cargo box from!