73 vw beetle external voltage regulator?

[GuardDawgs]

not sure if i have a gen or an alternator but i got a motorola voltage regulator that i got from under the back seat it has 4 wires coming out of it , a blue, green, red, and brown i have looked up new ones and found some but they are both bosch , if you can see this sight at the bottom it is the top one which is nothing like the one i have and the bottom one which is like the one i have but without the blue wire , so what i am wondering is if that will work and why does it not have the blue wire like the old one?? http://www.drivewire.com/vehicle/volkswagen-beetle/voltage-regulator/#1973 and the other is