At that temp I believe it should be ok. I would put the pyrex in while the smoker is cool if thats an option to be super safe. But there was a thread on here that has me a little timid on pyrex, especially now with a child running in and out of the kitchen.
The second link is in the first but thats the one that really gets me.
With all that said I have never had a problem with pyrex. But you never know.