Quick question about XMP IDs in Premier...

TL;DR: Skip to #1 below

I started editing a project on my new laptop, but I had not reviewed the preferences and the "Write XMP ID To Files On Import" box was not checked. I checked it, so moving forward PP should write the ID to new imports. Here's my question though:

1. Will PP write XMP IDs to the files I was already editing now the box is ticked?
2. If not, is there a way to force PP to do so manually?
3. Finally, if I cannot force it to write the IDs, how can I work around the issue (preferably without starting the entire project over again).

Thanks in advance!