Stevie likes to give people crescent moon pendants and crystals and stuff like that. I don't see her giving him an Eagles ring, but who knows.
I wonder if it was the photographer's idea, which would explain why Glenn is also wearing some Eagles jewelry he normally doesn't sport.
As for the Don and Glenn tux photo, their hair looks a lot like it does in this 1990 photo:
I'd guess it's pre-HFO when Glenn's hair was longer, post
End of the Innocence when Don had a ponytail. That puts it from 1990-1993.
I'd even narrow it down further - Don is sporting a full beard in
this photo from 1991, which I think makes it likely that this photo is from 1990. However, since he could have just shaved the beard, this could have been taken later... still, I'm going with 1990.
Also, Don looks like one of the guests rather than the center of attention. Still, Don is dressed up more with the white tie. Maybe he just felt like getting a bit more spiffy.
Glenn got married in 1990, but somehow I don't see him wearing sunglasses to his own wedding reception, or sitting at a table with Don drinking wine - I'd imagine he and Cindy would be together feeding each other cake and all that. Again, though, one never knows! The timeline would fit.