They were made from 1986 to 1989 and apparently S&W didn't make many before they began putting the full length underlug barrels on them. They look nice like that. I had one but, not being a particularly sensitive guy, I didn't feel much difference from my 1976-made gun, and sold it to another forum member. I have a 6 incher (seen much more often than the 4 incher) like that for sale in the marketplace section.
Many like the full length barrel underlug on the Models 17 and 617, but I don't find the extra weight needed or wanted on a .22. It's nice to have a choice.