Trying to find a specific (bad) Western novel

[Death by Chains]

Almost thirty years ago(!), I read one of the Doc and Raider Westerns by "J.D. Hardin" (actually an umbrella pen-name for several writers). The series was pulp macho bullshit about the titular pair of Pinkerton agents buddy-copping their way around 1880s America, shooting bad-guys and screwing (in varying degrees of explicitness) virtually anything in a skirt that crossed their paths. This particular installment in the series featured a goodwill visit to the USA by two members of the Japanese Imperial family, including various shenanigans with the Prince's samurai bodyguards, a frame-job for murder, and a climactic battle against a band of ninjas working for the villain.
Now I find myself in the position of trying to describe one of my characters encountering this novel themselves - only I can't remember its actual title, or the names of several key characters!
Does anyone have detailed knowledge of the series, or know of a forum where I might find such knowledge? Just putting a name to this specific book would let me hunt down a copy through Amazon (I hope).

 

[yourawoodbundle]

Try asking on reddit, like the tipofmytongue subreddit