Hello fellow S &W members.I am curious of the D sn on the s w mod10-5 SB .I picked one up last year at my local gun/pawn store. It is becoming my most carried and shot 38. The sn on the bottom of frame starts with a 2 then D then 5 more numbers. 2D75785 to be exact.Would this make it a D sn that is mentioned in a post by hardcase60 and what is the relevance or makes it desirable. Is there a difference in the SB vs RB that makes it more or less desirable or is that just personal preference. I will be searching this online but learning something new everyday on this great site and great stories. I usually have my 65-3 3in in my range bag everyday and sometimes carry a 66-1 2.5 in and don't carry my 19-3 2.5 inch as much. This 10-5 is a great piece.Thanks for any info in advance.