In 1965, the Wesson family sold the Smith & Wesson company to Bangor Punta Corp., who held it until 1984. In January of 1984, Lear Siegler Corp. of Santa Monica, California, purchased Bangor Punta Corp. and consequently, acquired Smith & Wesson. In December of 1986, Lear Siegler was purchased by Forstmann Little & Co. Forstmann Little, however, had no interest in Smith & Wesson and sold it to help finance the acquisition. Smith & Wesson was sold to Tompkins p.l.c. of London, England.
It's during this period that quality started to decline, accelerating in the early 1980's to truly inferior levels on some examples. I remember a couple of my own purchases in this time frame - one had just abominable timing causing the gun to misfire regularly, the other was a 8-3/8" barrel threaded at a significant side angle to the frame. That one spit quite a lot of lead, as you can imagine.
Thank goodness that phase of the S&W evolution is in the past - hopefully to never return. Current manufacture can't exhibit the same level of hand craftsmanship as in the "old days", but modern methods deliver consistently solid and reliable hardware. They're a better basis for customizing than most manufactured during the period mentioned above.
Cheers!