The first 3913 TSW's were the non-rail ones. They have a shortened grip and one less round in the mag. Supposedly the frame and slide were matched, making it a well fitted gun, though not a custom. There's a big "Tactical" on the side. They were made for only two years.
The current version uses the standard size frame and is basically a standard 3913 with a rail on it. Still says "Tactical" on the side.
I have an earlier non-rail 3913 TSW, and it's really an excellent CCW gun, even more compact than a normal 3913, but still big enough to not be a PITA to shoot. The mag floorplates are different on the non-rail TSW than the standard 3913 and current TSW because of the way they shortened the frame.
They used a standard 3913 frame and cut out the front part where the mag is and left the heel alone. It allows the mag to fit flush to the frame, though you loose one round. Because of the one-piece plastic grip, the floorplate is contoured to be flush with the grip on the sides. Size wise, it's like holding a regular 3913 without a mag in it. There were both flush and pinky extension floorplates. IIRC the gun came with one of each.
I'll try to take a pic of mine and post it here in this thread.