I can't tell you whether vacuum is needed via the parts catalog with any certainty, but I can tell you how to find out... check the passenger side axle tube on the front axle. If there is a cast steel (iron?) housing hanging off the back below the passenger side upper control arm mount (which should be part of the same cast housing) and some vacuum lines running to it, you need vacuum for the front axle. Otherwise, you don't!
If you don't have vacuum lines going to the front axle housing, you shouldn't need it for the transfer case either, as the transfer case just has a vacuum switch on it to engage the front axle when needed (and IIRC does not have the vacuum switch if the front axle is a "non disconnect" type one.) Your part time 4wd light may not function without vacuum (I forget how it's set up on the vac actuated cases) but seriously, who needs a light on the dash to tell them they just pulled the 4wd lever?