[AUCTeX] preview.el only works with 32 bit ghostscript?

[Ista Zahn]

I've been having trouble generating previews on windows, and finally
tracked it down to preview.el not finding gswin64c.exe (despite this
being in my PATH preview-gs-command was nil) installed from
http://www.ghostscript.com/download/gsdnld.html. I had to install the
32 bit version (also from
http://www.ghostscript.com/download/gsdnld.htm) and add that to by
PATH, after which preview-gs-command was correctly set and previews
worked. Is this known/expected that 64 bit ghostscript will not work?

Thanks,
Ista