Many scholars think so, especially those trotted out by the Discovery Channel, PBS, etc. A lot of scholars disagree, and for good reasons, but that isn’t as media-sexy.
Here’s a good article on recent re-consideration of the “earliness” of Thomas. It’s by Nick Perrin of Wheaton College, whom I know. Nick spoke as part of a lecture series I coordinated in Bellingham, WA a couple years ago on this topic. The article is a bit technical, but I think non-specialists in biblical studies will follow it. I post it since there is so much paleobabble surrounding the Gospel of Thomas. You all ought to know that it’s not so neat a picture as the popular media would have it.
Thanks for pointing this out, very useful! I actually follow a pastor who was very focused on the Gospel of Thomas and Gnosticism. Of course, such is the United Church of Christ at times.