The crimulous bill specifically states that the money cannot be used to build any of the prototype walls.
However, and this is just me but after a good deal of thought on the subject I have come to the belief that a double fence system with a path in the middle for border patrol trucks is a better way to go. Cheaper and you can really throw that stuff up fast. Put some concertina wire along the top of the fencing and you have a pretty effective barrier that you can see through for observational purposes. Less repugnant to ranchers and municipalities.
So Trump dips into some of that DOD money plus the $1.5 billion for the wall and tells the corps of engineers to start throwing up fencing. Congress can suck air.
It's a suggestion not a budget big difference. They carry different levels of meaning.