Mis Marked S&W Mod. 60

I have another post about this gun. It is a S&W model 60 with an AYN serial number and w/o a pinned barrel. But the inside of the crane area is only marked 60?? I will try and post a picture of this area. Could it be mis-marked?? Hope this link works. Thanks.
http://i152.photobucket.com/albums/s174/texasoldiron1/SWMod60Crane.jpg
http://i152.photobucket.com/albums/s174/texasoldiron1/SWMod60.jpg