Just checked my stash and discovered an Italeri RSO/3 Magrius towing a PAK 40 anti-tank gun kit. The RSO is the wooden cab version but I would imagine that the chassis and running gear is the same as your RSO/1, meaning the tracks would be common to all versions. The good news for you is that I discovered aftermarket tracks in the box, meaning that I don't need the kit ones.
You're welcome to them if you want them, on condition that I accept absolutely no financial reward whatsoever.
You can e-mail me with your name and address if you wish at gerry.walls@agriculture.gov.ie