what is a chevy GC3300 and G2300? Are these versions of the Express?

[Fordina]

Hi,
We are going to a government auto auction on Tuesday -- hoping to buy a 12 or 15 passenger van. They have these Chevy GC3300 and G2300 vans listed and they look like big vans, but are these 12 or 15 passengers or something else? I looked extensively online and wrote Chevy, and they said they didn't know what they were so obviously they're being listed at the auction under a different name than they would typically go by. Thought you folks might know....