Here's some information on the 'Boston Bulldog' revolver that I've been able to find:
* American Bulldog (Solid-Frame DA Revolvers)
With the introduction of the solid-frame double action revolvers in 1878, the four frame sizes and serial numbering method of the earlier handguns were carried over. These DA revolvers were available in centerfire calibres also, and in this series the .41 rimfire was replaced entirely by the .44 Bulldog and .44 Webley centerfire cartridges.
This is yet another revolver design which, though it started production under the Johnson & Bye partnership, continued to be produced by Iver Johnson Arms (& Cycle Works) for a number of years.
There are five different brand names known in the solid frame, double action series. These are American Bulldog, Boston Bulldog, Old Hickory, Eagle, and British Bulldog, with the American Bulldog being the most common model. All were
identical except for markings. This series is most often referred to by collectors by the most common name, American Bulldog. In this series of revolvers, there is justification to divide the production into three different models. There was a major change in frame shape about 1885, and markings on the American Bulldog were changed in 1899:
American Bulldog, First Type (1878 - 1885)
Saw-handle grip strap, square butt, 3 or 4" barrels.
American Bulldog, Second Type (1886 - 1897)
Rounded rear grip strap, square butt, 3 or 5" barrels. Also, a light weight version was introduced called the Boston Bulldog.
American Bulldog, Third Type (probably post-1900)
Same as Second Type except Model 1898 added to the marking on the top strap. There are strong indications that this type of marking was not added until after 1900, for the purpose of using up left-over parts after the introduction of the Model 1900 Double Action Revolvers.
Value on any of these revolvers in excellent condition probably won't exceed $200. Hope this helps!
Steve Mace