S&W Model 10:
1957: Begin stamping model number.
10-1 (1959): introduction of heavy barrel (the frame is slightly different for the heavy barrel, and changes to the standard-barrel variant were generally carried over to the heavy-barrel variant, thus the engineering changes happen in pairs)
10-2 (1961): change extractor rod thread for standard barrel
10-3 (1961): change extractor rod thread for heavy barrel, change front sight width from 1/10" to 1/8"
10-4 (1962): eliminate trigger-guard screw on standard barrel frame
10-5 (1962): change sight width from 1/10" to 1/8" for standard barrel
10-6 (1962): eliminate trigger-guard screw on heavy-barrel frame
10-7 (1977): change gas ring from yoke to cylinder for standard barrel
10-8 (1977): change gas ring from yoke to cylinder for heavy barrel
10-9 (1988): new yoke retention system, radius stud package, floating hand hammer nose bushing for standard barrel
10-10 (1988): new yoke retention system, radius stud package, floating hand hammer nose bushing for heavy barrel
10-11 (1997): MIM hammer/trigger + floating firing pin for standard barrel
10-12 (1997): MIM hammer/trigger + floating firing pin for heavy barrel
10-13 (2002): limited production 1899 commemorative edition
10-14 (2002): internal lock
I don't have my copy of the Standard Catalog of Smith & Wesson, 3rd Edition handy, so I don't know about the 17 or 19, suffice it to say that I do know:
S&W Model 17:
1957: stamp model number
17-1: eliminate trigger-guard screw
17-2: left-handed ejector rod thread
17-3: ??? (I think this one might have to do with moving the rear sight leaf screw)
17-4: ??? (I think this one is move gas ring to cylinder, in 1977)
17-5: ??? (I think this one is the new cylinder retention system, eliminate pinned barrel)
17-6: full-lug barrel
17-7: frame topstrap drilled & tapped, stainless cylinder/pinto
17-8: 10-shot alloy cylinder
17-8: 6-shot, round-butt, tapered barrel Heritage model
17-9: Internal lock
S&W Model 19:
1957: stamp model number
19-1: ??? (eliminate trigger guard screw?)
19-2: ??? (left-hand thread on ejector rod?)
19-3: ??? (move rear sight leaf screw?)
19-4 (1977): move gas ring to cylinder
19-5: eliminate pinned barrel, eliminate recessed cylinder
19-6: new yoke retention system
19-7: drill & tap frame, MIM parts? (not sure)
I could be way off for the 17 and 19, though...