Even though the use of a VF Maxbolt or SCP-4 provides the most accurate indication of clamp load (since it indicates direct tension), if you are using the torque method to tighten the joint you should still consider the merits of lubrication.
Since torqueing the fastener will involve rotational forces, the need to overcome friction will be important in order to deliver the optimum force to achieve the desired clamp load. Friction losses can been significant, so applying a light film lubricant to the fastener threads and under the bolt head will help reduce such losses and help in improving repeatability and accuracy of the process. Lubrication will not affect the clamp preload.
The good news is, since you are using a Maxbolt or SPC-4 product, you will know within a +/- 10 accuracy tolerance your direct tension or preload.