I think you've gotten wonderful advice already - the only thing I'd add is that this is just the very start of the school year and your ds is in a new program (I think this is his first year in the GT program?). I'm also guessing that since it's first grade a lot of the *other* students in his class are in the GT program for the first time too. It's not unusual in any classroom for the first week or so of school to be spent with the teacher giving the class assignments simply to see where all the kids are at - so your ds may be getting work right now that is easy for him but that might not be what he'll be doing for the rest of the year.
Good points! It is a very, very good idea to see what the plans are going forward. But I don't think it hurts to ask about the process, if you can't wait it out.
ETA: Also wise to remember that we're all complete strangers on the internet... none of us knows your particular situation and most of us respond based on our own experiences. There is tons of really useful information on this board, but the more experiences you read about, the more you're likely to get a good idea about all kinds of options, and you can pick and choose and tailor the advice to your situation.
