I was hoping this had been a recent development. I've never really liked Duff's tone; that thin pingy sound with a tiny bit of breakup and a washy chorus effect. He seems like a great pick player, saddled with a fairly vanilla '80s tone. I don't dig the GK 'rails' tone as much as some.
Agree with other posts, that T-bird has had an injury in the past around the jack socket. I did something broadly similar to my old SG when I was a teenager between a few cable yanks and at least one plummet to the floor.
I don't think the T-bird looks out of place on Duff. If anything I think those weird '80s PJ basses looked a bit too sterile and yuppy-clean-cut for a guy rocking the junkie chic look. I don't imagine he will be able to fret too accurately in leather gloves though!