I going to jump in and guess by the serial number, your Harrington & Richardson top break would be from around 1915-1920 range. Earlier H&R top breaks didn't include the cartridge markings on the side of the barrel. H&R started to include that information to designate that it was safe to shoot the then new smokeless powder. Earlier ones without the cartridge designation are strictly black powder models.
Also, the serial number appears in a few other places as well on the pistol. The back of the cylinder, the underside of the T-shaped barrel release latch and the underside of the top strap all should have the same serial number that's on the butt of the pistol. Sometimes the back of the ejector star has 2 of the serial numbers listed as well.
Value of these is not great. If it's in perfect mechanical shape and h had most of the original finish, maybe $275 tops. With a lot of finish missing, maybe $100.
H&R pistols were a lot less expensive to purchase in their day. If a new S&W sold for say $11.00 in 1910, an H&R of the similar design would be around $4.
I hope this helps some what. As others have said, a picture would be very helpful!