That's a very good question, Bill. The 60 was actually introduced in 1965, the 60-1 came along in '72, and the 60-2 was 1987. Both the -1 and the -2 were limited production special runs (171 and approx. 2500 pieces, each, respectively), so it appears that the "no dash" continued in production in parallel with the -1 and -2. The -3 came out in 1988, and I assume at that point all the 60s became 60-3.
There's no question that the "AND" prefix was used in 1986; the 3-character alpha prefix system for all S&W revolvers was initiated in 1980. As another check - look for a pinned barrel. That feature was dropped in 1982, so your revolver should not have one.
There's no question that the "AND" prefix was used in 1986; the 3-character alpha prefix system for all S&W revolvers was initiated in 1980. As another check - look for a pinned barrel. That feature was dropped in 1982, so your revolver should not have one.