I don't know if they changed the 500T throughout the years, but mine is from 2022 and it's brighter than my Custom. Had them both in the same guitars.
Both are pretty sizzly in the highs, but the 500T has a lot of those those Duncan Distortion high mids as well, so I feel it comes off as noticeably more aggressive. I wouldn't say it's BL levels of bright, but it is more aggressive than the Distortion or the Custom, IME.
I've often read the 500T being described as fat, and mine is the opposite of fat. It's a very focused aggressive pickup. The Custom has a way fatter low-end than the 500T to my ears. But maybe the old ones are different?