I put a pre 29 4 screw on hold today. It's a 8 3/8 not a mark on it. Has the coke grips and the screw is locked up with green corrosion. Couldn't get the grips off, they do have a small chip its on one side behind the trigger guard. Otherwise they are mint. The serial number is S1776XX. It has a clam shell box and the insert is about 80%. The tools are there but the sat is from a later gun. I know the longer tubes bring less money what do you think a fair price as described?
Always I look to the guys here to guide me on the older guns
My pre 29 four screw came in a dark blue/black box serial number S181xxx, and shipped 1958. Although yours has an earlier number, I understand the 8 3/8's were introduced with the walnut pres cases, and not the blue/black box. The clamshell case came in around may 1960, maybe earlier, so if your gun shipped later than the serial number would project, then it could be original. A factory letter could nail it down.