I have never heard of anyone being told what tier they are in. The only way you know you are in "tier 1" is if they give the invite and it's just generally announced they are hiring from tier one. Even then that doesn't mean they may not randomly pull from tier 2 intermittently. No one really knows except the selection team.

Even though many do interviews it does not mean they are on the selection team. It appears the selection team is a much smaller group than the interview team. Spoke to a guy who does interviews and he said he doesn't know how they rank the tiers because he has recommended some and he's not sure which ones his candidates are in. Again this gentleman was on the "interview team" not the "selection team".

Just like freezingflyboy said above, even if they knew they probably wouldn't tell you, but this guy I was talking to really seemed to not know.