I just joined myself. I have attached a PDF that is a fairly extensive list of GM RPO Codes. The paint codes are listed at the very bottom of your RPO tag...the "WA" and then the "L 9204" is supposed to stand for the "Lower" paint which should be the stripe and the "U 8798" should be the "Upper" which will be the grey. The only thing that has me confused is that the GM paint code "WA9204" comes back to a Mesa Brown which is NOT what the stripe is. The "82D" is your interior trim color which, according to the RPO file I'm attaching, is a Medium Grey. I spent more than 20 years in GM dealership parts departments starting in 1992. These trucks were still everywhere on the roads and were actually still coming into the dealerships for service. I'm by no means an expert but I've got a lot of experience on the parts side of these trucks...looked up thousands and thousands of parts for them. Also, I've got a PDF version of a 1987 GM C,K,R,V Service manual and the 1987 GM Ignition and Emission Service manual supplement I can send you...not sure if the site will let me upload a file that size. Like I said, it's a 1987 but your 1988 shouldn't be that much different. Good luck with your rig!
