> No, at least not for Chez.
>
> (display '#&123)

That works, too.

I've updated <https://registry.scheme.org/#hash-syntax> and added the
following note: "A quote ' next to an implementation's name means the
syntax must be quoted in that implementation."

The entry is now:

#&...	Box ['Chez, 'Gambit, Racket]