I cannot (and won’t!) comment on the nutritional breakdown, as that should be pretty easy to figure out from looking at teh back of the containers.
I will say that I regularly take a pbj with me on bike rides (crust and all) and have yet to suffer deleterious effects from its consumption. I have also eaten one on my first HIM before I realized I work best on an all-liquid diet for racing. It wasn’t from a GI perspective that I moved away from solid foods and gels, but rather convenience of just drinking liquids.
Remember that grand tour racers often eat a proper lunch sandwich while riding and seem to manage quite well despite the fact that bicycle races are far from the steady-state events we participate in. If I were to attempt an iron-distance event, pbj’s would likely be a part of the race diet. They’re surely easier to eat than f&*#ing gels.