The OEM haead gasket for the B20B is 0.030 in, which retains the high compression, and Volvo no longer sells these. That gasket is thinner than the one you have, although the thinner gasket may require premimum fuel. The one you have is a good compromise. The gasket for a B20E may be still thicker than the one you have.
I would measure the bore on that engine. There's a very good chance that with all the work the head has seen the motor is a bigger bore, like 2.2L and any stock Volvo head gasket will be too small. In that case, you will be looking at a diferent gasket, but they are still available aftermarket.
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'89 245 sportwagon, destroyed by hit & run driver, RIP. '04 V70 2.5 T Sportwagon, 12k mi and '91 245 5-speed, 209k mi, replaced the '89