If you can get the gun in hand to look at it, the 38 S&W is about the length of a 9mm, but slightly fatter than 38 spl. Looking in the chambers, theres an obvious step where the 38 S&W chamber ended, then another step where the 38 special rechamber ended.
If you cant get to it in person, see if he will take a clear picture of the chambers.
Found a picture, it shows it pretty well once you know what to look for.
http://www.fototime.com/F07416FB0193628/standard.jpg