Ideally, you want the strings to run straight through the nut slots , leave the nut with a slight downward angle and have a straight run to the tuner post without touching anything else. If that is possible without the guide, then you don't need it, but if they run up against the other posts then you need the guide to relocate them.
It's hard to tell in the photo if they would hit anything or not. The only way to really tell would be to remove the guide and restring and see if they hit anything other than their intended target.