Hi Marshall,
The George Bush PS1 boxcar was a custom run by the METCA and was available only through them. I don’t see it listed on their website currently but you can try here:
https://www.metca.org/store.html
Also try through Stu Rankin (who is a forum member) as he may have some leads, since he is the wonderful person behind most of these of custom run ideas for METCA.