Hello Elliot,
I just came to this thread looking for a similar answer. I thought (or hoped) perhaps Premiere CC might have addressed this.
The previous answers are correct that Premiere has historically not used the .thm files to pull the camera time of day “timecode” into the file to create a sort of pseudo timecode as FCP used to when importing/transcoding DSLR files.
My workaround in Premiere for the past few years has been to use a third party program called qtChange prior to importing into Premiere to add the time of day camera timecode from the thm file to the mov file. You can also use qtChange to add a reel name to the mov file which can come in handy when sending edits for color grading as the reel name is sometimes very useful in color grading software.
Once qtChange has added the “timecode” to the mov file, you can import it into Premiere and now Premiere will see the timecode as it’s now part of the mov file and the fact that Premiere doesn’t read the thm is no longer an issue.
It’s an extra step before importing, but so far, it’s the only easy way I’ve found to make sure my DSLR files have a more useful timecode than the 00:00:00:00 since there technically is no timecode in the original mov file.
I hope this helps. And it would be nice if future versions of Premiere would be intelligent enough to notice the thm file and pull the time of day timecode from the thm file.
Billy