Well if you read some of the factory correspondence there was going to be approx 2500 6.5's and 2500 4's made with the 6.5's being first. Smith made more 6.5's due to demand in the first run so the 4's didnt start until the end of 1956. We know there was at least 2-3 dozen 4" guns shipped in 56, but we only know the whereabouts of <12 or so. So, if your gun will letter to 56 it IS scarce.