If I'm not mistaken, the CC Glenn and Glenn from CT are indeed two different people.

I can see how people would think that they are the same person though, especially if you see the PSX version of CT and get the ending where you see Glenn back in human form. They kinda look similar, and they both can weild legendary swords and this and that. They are two different guys though. I can double check on that though. It's been a while since I've played CC or CT, and I haven't played through CC as many times as I have CT.

Hey, I remember that part in Xenogears!! ROFL!! Big Joe was a pretty funny guy, ya think? ^_^