Around 1990 - dating the revolvers with the 3 letter prefix serial numbers isn't as precisely listed in the SCSW (Standard Catalog of Smith & Wesson) as are the older serial numbering systems.
The Model 37 is the Airweight Chiefs Special, same gun as the Model 36 but with an alloy frame. They make very handy carry guns, and some will bob the hammer spur for pocket carry. As it has an alloy frame I would not feed it a steady diet of +P ammo, others claim it should only be fired with standard pressure ammo, and still others feel it will hold up to unlimited +P use. "Carry a lot, shoot a little" is the phrase often used about Airweights. Enjoy it and post back if you have any more questions.