Doubt it
Not possible
It seemed too low to me also. I remember when Claude Groulx won the 2003 Master's Mr. Olympia contest, he said he was 3.5% body fat, and while there have been bodybuilders a little leaner than him, I also wondered how accurately these body fat percentages are being reported.
We all know the example of Flex Wheeler testing at 0.0% body fat in Gold's Venice by Jim Quinn.

Lou Ferrigno said in a scene from a radio interview in his Walking Tall training video that he was 1% body fat. It's incredible how these guys either lie, or...just have no clue, when it's already incredibly hard to do what they do, but they need to make it seem even more unrealistic by stating that they train six hours a day, or are 1% body fat or whatever.
I'm trying to think of a realistic body percentage for me, while having a diet that isn't too restrictive and generally not using anything to help me with that [nothing I would take regularly I mean, if anything at all], and I think 15% is fine. I say this knowing people falsely think 15% is 10-12%. Again, to be in shape without going overboard. A year-round shape, basically.
I was under the impression that bodybuilders might get to 4-6% - which we call "3%", but given that the organs have visceral fat that can't go away completely, that it's not possible to go much lower...without dying.
So a 250-lb bodybuilder at 6% body fat would only have 15-lb of total fat in his entire body. Given the aforementioned organ fat, this seemed more realistic than claims of 3%, which would only be 7.5-lb of total fat in the body. That just seems extremely low to me, given we need this visceral fat, in order to survive. But I'm not sure on that.