I don't think so, because the bomb itself was described as "amateurish". If there had been lots of planning involved here, you'd have to assume they would have put more effort into making the bomb. Rather, this suggests to me that whoever may be responsible has some connection to the used car or salvage business directly or indirectly, because that part of the plan, unlike the rest of it, was done with considerable skill.
I think that the label "amateurish" is amateurish. With some motor oil, fertilizer, and detergent in a truck packed with gasoline, propane and a couple of hundred packs of of bolts, nails, nuts and use a cigar or a cigarette as a delayed fuse is pretty simple and amateurish.... but effective. Heck just because it's simple doesn't make it any less lethal. I'll wait and see what the guys investigating this find out. It sure is going to be interesting to see how this pans out.