Do you need to oil the bushings in a doweling jig?
This is a good question for the woodworking site, but I would not oil the guide, the oil will stain the wood. Do use care while using the guide, use sharp drill bits that will not need to be forced to hard to drill. The more force you use the better the chance of angling the bit in the guide, wearing it out prematurely, and making the dowel go in holes that are not in line with each other. Brad point bits are preferred here. Purchase drill stops too, if you don't already have them...