Thanks guys for your replies. I ended up solving my problem another way.
@ratpack: yes, you are correct in what you say, but the tyres are big $$$
@Wavey: yes, that is what I was chasing, but I think that placard is newer than GC. I was told a GC8 came standard with 205/50R16. I was just hoping someone with a GC8 would give me a pic of what they have affixed to their vehicle, so I could determine the largest tyre option available to me.