Thermite,
That's right it has been rebored 2 sizes over standard. Oversize sizes are 0.25, 0.5, 0.75 and 1.00mm. That means that if you are putting new rings (without rebore) you need to get some 0.5mm oversize ones. Heres the DRATV page where the dropdown lets you choose the size.
http://dratv.com/noname44.html