Hi guys, I'm a newb to S&W revolvers. Actually this my first revolver. I'm an auto guy, so be kind to me. Soooo, I picked up a 686, no-dash, serial# AAD61xx. I'm hoping someone would be kind and give a rough production date. I know, "BUY" the book. Honestly, $35 for a book to look up a single serial# is a bit stiff. So, any help would be greatly appreciated.