Can anyone verify if it is a Type 4? Based on my research, S/N range and configuration I believe it's a Type 4 or a transitional Type 4 and if it is a Type 4 then according to Bill Hamm he says (quote) "Fewer Type 4s were made with 4-5/8” barrels than the other individual Types 1, 2 or 3 in that barrel length and are quite scarce". (end quote) Thanks in advance for any info.