Scott doesn't look like he's lying in the video. He seems more bemused, than anything else. Besides, he looks healthier than he has in almost a decade... Certainly doesn't lend credence to the "on meth" thing.
The anachronisms in the arrest record, the lack of prior discovery (again, this was four weeks ago), the lack of tour cancellations or any word at all from Scott's camp prior to now, and most of all the source of the information being TM-fucking-Z... Eh, I call bullshit.
I think a guy named, or claiming to be, Scott Weiland got arrested for possession of meth. I think some cop told TMZ about it, and TMZ didn't bother to check if it was THE Scott Weiland.