John,
Here's what I've found. I think you're correct about the website. I first saw them in a K-Line catalog that I picked up at a show a couple years back:
Pennsylvania | Pass Car, Streamlined | Observation | K4680-38424 | 1999 | 18" | Spirit of St. Louis, 'Alexander Johnston Cassatt' (Black/Gold Box) | Aluminum | #8424 | |
Pennsylvania | Pass Car, Streamlined | Pullman | K4680-38060 | 1999 | 18" | Spirit of St. Louis, 'City of Reading' (Black/Gold Box) | Aluminum | #8060 |
You may want to check these though; they may already be in your 4-pack set.
Mike