Pretty sure you will only find new ones in 9mm and 45. Even IRGs only has the standard USP in 40, not the expert. Bullseye and Wanstalls have them in 9mm and 45 I think. 9mm and 40 use the same sized platform in the Expert. The 45 version is scaled up.
And just on the versions, some kits come with an aluminum case and a jet funnel. I think the current crop in Canada are packaged this way however the jet funnel/magwell is not mounted on the gun, nor does the package come with jet funnel compatible mags (I suspect because HK does not make/factory pin them to 10 rounds). If you add the funnel after, you would then need to source different mags.
IRGs has both versions. It is possible their jet funnel version comes with the proper mags and they will just pin them. The version without the funnel and Al case is about $120US cheaper.
Be careful ordering USPs from IRGs. The pictures and descriptions are often different and it is the product code that matters. Eg the gun on their sight for $1327 us has the picture of an Expert, but part of the description does not match so you need to verify. I lived this problem even after verifying multiple times....