Wow, glad to see the Highlander discussion raging on! I started the referenced thread in the original post here, you can see my truck doesn't have the 'promo package' SPID, but it sure does have 'Highlander plaid'. My theory is that early Highlanders didn't have A, B, and C packages, but I don't know what, if any, options came with it besides Custom Deluxe trim.
As far as getting the Highlander plaid completely separately, I don't know. Wouldn't it be great if we had a member here who was in Chevy truck marketing back then, and remembers how the Highlander evolved?
BTW, just yesterday ordered up orange plaid and embossed parchment from SMS to do the seat in my truck