Looks like Craig beat me to the punch. I dug out a couple trim rings and one had a tab on top and the other didn't. I couldn't dig out a headlight bucket easily - i did find the bulb portion but that didn't help, so I took a trim ring off my truck. Like Craig's pictures, my trim ring uses the spring clip to go into the slot at the top of the bucket.
The spring clips for the seal (available from the usual suspects) will provide that tab to secure the top of the trim ring. Looks like Craig needs to invest in some new seals.
I was mistaken about the seals having nothing to do with holding the trim ring on. Sorry, it'll never happen again.
Here's my pics.
