Re: Use Serial number to determine Chiefs special age ?
That format is the way numbers are issued by BATFE to replace numbers removed or obliterated for whatever reason. S&W does use a 3-letter, 4-digit numbering system, but it would not be that format and would not have an additional series of numbers.
I think that gun was marked with a number assigned by BATFE. There is no reason it should not meet any logging or registration requirements.