Dyna Glide ModelsSuper Glide, Super Glide Sport, Super Glide Custom, Dyna Glide Convertible, Super Glide T-Sport, Dyna Glide Police, Dyna Switchback, Low Rider, Street Bob, Fat Bob and Wide Glide.
The FXDX had a higher ground clearance that enabled it to carve canyons a little cleaner. Also had, I believe, some fabric expandable saddle bags and an adjustable windscreen on a small fairing. The FXDC was a chromed out Superglide that was offered when the Lowrider was taking a year off for some design changes. I haven't seen the OP pictured bike on the site, with those rims I think I would have remembered it. Have you checked other HD websites?
I would say that if the previous owner were a member here, he probably will be too embarrassed to admit he did that to that poor Harley. I'd check the sport bike groups. That's the styling they seem to like...