If this shop did an alignment on your truck, you should go back and insist on another realignment "UNDER WARRANTY" after you get your new tires put on. If they will not do this then ask for a refund on the alignment, and if they will not give you a refund, then remind them that your State Bureau of Automotive Repair (BAR) says that is illegal to do alignments on vehicles with worn out tires.
The reason I say this is because an alignment on worn tires is a waste of time. Worn tires will sit differently on the alignment plates than a set of fresh tires will, thus resulting in improper adjustment specs on the alignment rack.
The reason I say this is because an alignment on worn tires is a waste of time. Worn tires will sit differently on the alignment plates than a set of fresh tires will, thus resulting in improper adjustment specs on the alignment rack.