^^This.^^
Also , I don't think that front sight orange insert is a factory install.
It is red..just a bad camera shot..
also, I have a Model 57 that is actually stamped 57-0 and upon closer inspection found that the frame was actually a 29-2..Smith & Wesson stated that by serial number it is a 57. Someone suggested that they ran out of 57 frames that day and borrowed one off another bench..was wondering if this is the same issue here, will be calling them tomorrow!
Likely the HP barrel took on a bit of a polish job?