I have trusted that both my 1998 cars would have the new tensioner based on feedback on forums, which turned out to be wrong both times. I would recommend pulling the timing cover and having a look before purchasing anything. You can buy a bracket to adapt to the new tensioner, but Subaru dealerships don't stock it. Since I can't find a parts car locally I am stuck waiting 3 weeks for the bracket for my 1998 LGT.
Edit: just saw that you have an EJ22 and not the EJ25. There are a ton of SOHC Subaru's at pick n pull so even if you were wrong about having the new tensioner you can just pull a bracket off a 1999+ legacy/outback or an impreza. DOHC motors use a slightly different bracket so I am stuck.