You can run without spacers, but the inside of the front tires may "kiss" the strut tube if 195x15 or fatter, like 205 or 255, etc. No problem at the rear.
This based on my experience with an '85 240turbo that came with 850 wheels.

240 offset = 20mm
850 offset = 43mm
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Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

you need a set of spacer between 15mm and 20mm in thickness.

Bolt pattern. 240s all have a 5x108mm bolt pattern, same as 850s, iirc. You will probably need spacers to get the correct offset on the wheel though.

All Volvo series cars have the same bolt pattern through the 900 series (200, 700, 800 series inclusive). The bolt pattern for your car is 5 x 108cm. The 200 series has a medium offset while the later models have a high offset. This will put the tire a bit closer to your fenders but shouldn't pose any major problems. One option would be to take your car with you and ask if you could try one on for size, assuming the seller is willing. Good luck, ---rick