Smith & Wesson Model 90

gargoylecollector, here is some history on the S&W handcuffs you posted.

After Smith & Wesson discontinued their relationship manufacturing handcuffs for the Peerless Handcuff Company in November of 194o and after focusing their efforts for WWII, Smith & Wesson decided to start manufacturing handcuffs again, only this time patented with their company name and logo.
In 1952 Smith & Wesson introduced their new handcuff advertised as: A New and Improved Model by Smith & Wesson Premier Manufacturer of Rotary Jaw Handcuffs (see photo #2). These first handcuffs did not have a model designation assigned to them. It wasn't until 1958 that S&W started assigning model numbers to their handcuff line (see photo #3). The Model 90 was manufactured until 1979. The handcuffs S&W manufactured prior to 1979 did not have the model number stamped on the handcuffs themselves, but only marked on the boxes. When S&W introduced their new line in 1979, the Model 100, they began stamping M-100 on the cuffs.
In photo #1 on the left is a early model with the box only marked; Smith & Wesson HANDCUFFS One Pair Nickel. On the right is a later version with the box marked; SMITH & WESSON REGULAR FINISH NICKEL MODEL 90.
To differentiate between the early version and the later version of the Model 90 handcuff you need to find the location of the elongated detent, the indenture stamping (below the keyway), that creates a dog to engage to the pawl ditch on the jaw arm. On the early version the detent is located between the keyway and the center of the lock case (see photo #1 handcuff on the left). On the later version, the detent is located under the keyway (see photo #1 handcuff on the right). I am not sure when this detent change took place, but in the product brochures I have, the photo of the handcuffs shown (see photos #2 & 3) are of the early version through 1971. I do not have a brochure for 1972 & 1973, but in the 1974 brochure the Model 90 handcuffs show the detent under the keyway (see photo #4). Also in this brochure it identifies the handcuff case as B70 (like in gargoylecollectors post). In the 1971 brochure it identifies the same case as #70.

gargoylecollector, this might help you get an approximate date for your handcuffs. If you plan on keeping these, I might have an extra Model 90 box I can send you.

Dave