You might have a set of Virgo's from earlier cars, before Volvo started using the "locating pins" and correspondingly designed a hollow spot in one section of the wheel for that pin.

I have Virgo's on my wife's '93 240 (and Hydra's on my own '93 240) that fit without a problem. But I use snow tires in winter on old steel wheels without the hole for the pin, so I just unscrew the pin (10mm wrench) for these winter wheels and then reinstall the pins with my summer tires. It's no big deal to remove the pins -- the rotors are really held tight by not only the lug nuts but also by the second "non-pin" 10mm bolt, not to mention the caliper as well.