S&W started their line of ammo in the early 1970's and stopped in the early to mid 1980's.
Their line of 38Spl ammo had the most numbers of different loads out of all of the calibers they sold. They marketed over 10 different loads (including their line of Nyclad coated bullet loads). Bullet weights varied from a 95gr JSP round nose to 158JHP/JSP and a lead SWC-HP+P.
Unless you're a collector of S&W ammo or you'd just like to have the ammo, $20 would be a fair price. If it's for shooting, I personally wouldn't spend more than $15 a box for 25+ year old plinking fodder.
