I apologize, I gave you bad information. The white wire is the hot wire. The black wire goes to round, which is were it will go when you connect it to that center lug on the push pull switch. You would use the black wire as the hot if you needed to flip the phase of the pickup. You will want to check to see if the new pickup is the same magnetic phase as the one you are removing. If they are not, you will need to flip the hot and ground wires on the new pickups to put them in the same phase or it may sound thin and honky when combined with the middle pickup. The red wire is the tap wire.
Do you have an orange wire? Also, the new 4 wire PRS pickup I just bought doesn't have a green wire on it so I am wondering about that one as well. Are you able to take some pictures of the wiring in the cavity of the guitar and post them? That may help.