yeah just measured the offset. the wheel is stamped ET45 but when i measured and worked it out the wheel is actually only 35mm. 10mm error. I'll contact the manufacturer and see what they say.
1, If you purchased wheels made by a reputable wheel manufacturer it is unlikely that the wheel is stamped with the wrong offset number.
With the wheel off the car measure the backspace on the inside of the wheel. Measure from the centre mounting pad face back to the outer edge of the rim.
For a 9.5 inch rim..........
If a 35 offset, it will measure approx 169 mm or 6.6 inches
If a 45 offset, it will measure approx 179 mm or 7 inches
Even if the 9.5 inch wheel is +45mm offset as stamped it is still possible that with sufficient suspension travel the face of the tyre will rub the guard lip if you are running 275 wide tyres.
2. IF you were purchasing 45 offset rears and the wheels are in fact 35 offset the retailer has an obligation to take the wheels back and replace them with what you were told you were buying - ie the correct product. Clearly a 35 offset wheel stamped 45 and then sold as 45 offset is the equivalent of a faulty product.
3. If you are going to get the guards rolled do not use any cowboy with a rolling machine that says he can do it for you. Sydney Guard Rolling has a good reputation and you will not have to worry about the guy cracking your paint or otherwise damaging your car.