This may sound like a dumb question but I will ask anyway. I have 6 1st gen SAA's ranging from the oldest (1881) to the newest (1916). 5 of them have 4 digit bin numbers on loading gate that match all of the places they are on the guns. 1 of them (the 1916) has a 3 digit bin number that matches all over that gun. My question is did Colt use bin numbers for builds in any particular order or were they randomly assigned for each gun? I'm sure there were only a finite number of bins for builds and that they were most likely rotated through each year, or multiple times a year depending on production. Thanks for any info you guys may have on this. BTW, the bin# on the 1916 is not the last 3 of the serial.