1998 V70's do not use EGR. I believe 1997 850 was the last year with an EGR system. I think all 1998 V70's do have an SAS system. You can check the data plate under the hood to see what systems are in place that affect emissions. For example, my 1998 V70 T5 lists:
- SFI sequential fuel injection
- TC turbocharger
- CAC charge air cooler (intercooler)
- H02S(2) 2 heated oxygen sensors
- TWC three way catalytic converter
- AIR secondary air injection system

If you're not the original owner, it's conceivable (but unlikely)that the SAS system was removed by previous owner. Check out the air pump replacement writeup on bay13 (volvospeed.com) for pictures to see what the SAS components look like and where they are located.