I have a lift kit ordered from "Strong Made"...and they mentioned that they had this rear basket available.
571 - Universal Rear Bed Basket Rack For UTVs
571 - Universal Rear Bed Basket Rack For UTVs
that's what i have noticed and im thinking it will take some time for them to eventually show up, at least for now those that really want it will likely go the DIY routeI'm sure you could find some way to put a rack on the Viking, but I haven't seen anything that you can just buy as is and install. You may have to venture into the area of DIY a bit.
There could be gun racks of some kind available though, maybe just not quite the same as the ones that are shown on this other forum that you provided a link to.