I can save you some time on that- I'm an attorney. The only obligation that RAM has is to install the missing parts. You have around $1,200 in missing parts. It will cost you more than that to hire an attorney. They have already taken steps to make it right. IF they decide not to (which is a huge assumption since they already got your parts in), take them to small claims court. Anything under $12,000 in PA qualifies for small claims.
But why is anyone even talking about suing them when they have literally called and said that the parts are in and the customer needs to make an appointment have them installed? I suggest making that appointment to have them install what was left off, and then enjoying the truck.