LUNDSC00:
AYD5xxx is the serial number, dating it to late 1987.
686 is the model number, meaning a stainless steel L frame Distinguished Combat Magnum.
CS-1 is the designation for the US Customs Service variant. The product code is 104228.
M stamping designates modification under a recall with a new firing pin and bushing fitted.
aprosody:
Your Model 36 Chiefs Special was manufactured in 1969.
JesusismyPapa:
The serial range S305000 to S329999 was used in 1968 & 1969 for N (large) framed revolvers. 1968 seems likely as the year of manufacture for your gun. If the grips have an uncheckered diamond around the grip screws then 1968 is more probable, as the diamond grip was deleted in 1969.
felbie:
The Model 28-2 you are looking at was manufactured in 1973. The 28-2 Highway Patrolman was the service grade sister of the model 27 .357 Magnum, lacking the high gloss finish and checkering of the topstrap found on the Model 27. Introduced in 1954 and discontinued in 1986, in recent years values have started to increase as the higher quality Model 27s have become attractive to collectors, dragging the cost of the Model 28 up as a shooter grade gun. In 2006 the Standard Catalog of S&W gave a value of $375 in excellent condition. I would expect to pay closer to $500 or so for a similar gun now. I suggest you look at completed sales on some of the online auction sights such as gunsamerica, auctionarms, etc, to get a feel for current prices.
oldsgm:
Your Model 64 .38 Military & Police Stainless was manufactured in 1973 or 1974. Serial range for those years was D510001 to D659901, so 1973 seems likely.
bluto:
Your Model 36 Chiefs Special was manufactured between November 1985 (ALCxxxx) & July 1987 (AVBxxxx). My guess is early 1986.
woodlecj:
The Model 36-1 Chiefs Special 3 inch Heavy Barrel was introduced in 1967. The number you are quoting is too low to be the serial number, as it would have either six digits or a J prefix. What you are quoting is propbably an assembly number, used to track parts in the factory. The serial number is on the bottom edge of the grip frame. If the gun has custom grips you may have to remove the grips to see it. Check it and get back to me.