Wiper motor question

[Solver]

The wiper motor is going out on my truck. It moves real slow at both speeds so I guess it's time to replace it. This truck has A/C so it is unbelievably tight with hoses and such back up underneath the dash. Anyway the question is which wiper motor will I have? I ask this because LMC shows three different wiper motors for our trucks. 67-68 one speed --67-72 3 terminal 2 speed and 67-72 4 terminal 2 speed. I never knew till I came across this there was any difference in all the years of our trucks. Any way is there any way to know before ripping all that out under there which it might be for ordering or salvage yard searching. I have an extra that I think is a 3 terminal but hate to rip everthing out only to find out mine is 4 terminal . Just wondering if there were guide lines on which got what?
truck is 72 cheyenne super

[Sammy]

Not real sure what you have in yours. But if you pull the glove box ( cardboard) and the hose off the defrost tube that is in your way then lay on your back upside down you can pull the plug off the wiper motor. There should be two plugs the upper one is the plug for the wiper motor the lower plug with two wires is the one for the squirter pump which is attached to your wiper motor. Then you will be in the know exactly what you have. Wouldn't hurt to remove your cowl under your wiper arms remove & lub those mechanical arms with some light weight oil or WD40 or such.