I'm not sure.
The difference between a DT and a WB is that a DT has no choil. For those of you who don't know what a choil is; its that thing in front of the guard before the blade starts.
On the model DT, the lower guard came up at a 45 degree angle, then back down, to where the blade began. It was, it the day, a stronger design. The reason being that we had none of the cool guy steels that we use today. You had to worry about things like "two opposing right angles". These days it doesn't matter. So we go with the more useful blade/handle style.
Carpe Diem
Mick