This I am sure it was not .38 spl. The owner said it was .38 long colt. The markings on the barrel was like 38 S&W cartridge maybe.
Well this is highly unlikely. I am sure that it is 38 special, if its 38 cal. 38 S&W is out because of the configuration / age of the gun. 38 long Colt is basically out as well, because only the below 1899 US contract guns were in that caliber. Its possible that it was special ordered in 38 long colt, but since 38 special chambers 38 long colt, there would be no reason to order a revolver that way, esp one that isn't a target revolver.
The most likely scenario, BY FAR, is that the shop made a mistake. The roll mark for 38 special was not always simply "38 special" They would add "US Service Cartridge" so people would better know compatibility of the guns and rounds. This would be phased out later.
See below on a 1905 1st change M&P:
FYI - its really rare to find anyone at a gun shop who really knows S&Ws, and even when they do, its rarely the earlier 5 screw guns that they know. Most S&Ws are in S&W calibers, and any S&W in that era that is chambered in a Colt caliber is pretty scarce collectible gun today.
Despite all of this, looking at the photo, the gun to my eye looks like an I frame in 32 long. The trigger guard doesn't look like a K frame shape and the cylinder height looks too short to be a K frame. Also the trigger and hammer look smaller than that of a K frame. Thus, the barrel would be a 4.25 in barrel. With the SN of 167XXX, it would be a model 1903 5th change.
Smith & Wesson never chambered a revolver is 38 Long Colt. It was always a 38 Special way back to the Model 1899.
Gary, never say never with S&W

(38 U.S. Service Ctg = 38 long Colt)