Yes and no. Is there something you think is special about your pistol? Off the top of my head for instance, does the serial # fall in the range of being shipped to the Marine Corps? I'm sure one of the more knowledgeable guys will chime in.
I had a couple 45 Colt revolvers that were a fairly low serial range one time that I did the letter on. They had not been anything special that I could find out about them. Have no idea it it made them worth more or not, but it was interesting to know where they started out. I got another letter for a Colt 1903 .380 hammerless. It was sold in a hardware store in Dallas in about 1914 if I remember the year correctly. I still have it around here somewhere.