Default [Q] Former MyTouch 4G owner, SIM lock question

I'm hoping there are still a few people around that can help me.
I got the MyTouch 4G shortly after it first came out. I loved that phone, but then after moving to Europe I found myself needing a phone for the service here so I sold mine on Ebay. My parents both got them as well and now that THEY've moved on to other phones, I've inherited them.

My questions...
1. I rooted these phones about 2 years ago, but I have no idea whether they're SIM unlocked. Is there a way that I can find out?
2. If they're not SIM unlocked, is there some way I can reroot them to be?

Thanks, guys.