Welcome aboard, Chris! Sounds like you had a good smoke, but need a better thermometer!
If the butt had truly been at 165, the bone would absolutely not have pulled out clean.
As has been said, this is a learning process, and it sounds like you're on the right track! Good luck with your future smokes, and let us know how we can help! Be sure to post some pics, if able...we
love pics to drool over around here!