no down side to doing it this week.
As you suspect, since these are full body workouts, the thought is if you always work like M,T,Th,Fr you won't have sufficient recovery time between workouts (though that schedule would work for a different program, like an upper/lower split).
Try it. Work out on Thursday and then on Friday and see if you notice a difference in how the 2nd workout goes - or if you are just wrung out on Saturday
Haven't read NROL in a while to see the context.
To the other question: Something is always better than nothing I think but if you miss a week it won't be the end of the world either. You can always do a body weight workout at home so that you are not missing a workout, just not doing the prescribed one.