CDNN would be the best place to find one I don't know if they have any new in box ones or not still left. The ones imported for KBI imports are the best they send them back to the factory in Hungary and have them refurbed to like new.
CDNN also carries extra mags there a little pricey but it's a good idea to have couple extras you never know when you might need one and can't find a replacement.
I like the PA-63 because of the traditional rifled barrel,shoots cast bullets better than the polygon rifling like the CZ-82 those are nice pistols for the money and come with two 12 rd. double stack mags. and original holster so not a bad deal there either.