That's true, but if you just compile wxWidgets with the default options(on linux, unix), and you have Gtk2 installed ( which most systems do), it will be built as the Gtk2 port. So it is highly likely that most wxPerl's that get compiled, are using the Gtk2 libs, unless they were specially compiled.

I don't know what the windows precompiled binaries are based on, but it may be gtk2 also.