It is very quick to pull the rocker cover and check - what is the build date of the car/motor?
My 96' has roller rockers with hydraulic lash adjusters. About 3k miles ago I changed oil, t belt and resealed the front cover and rockers and everything. I developed a tick that got louder over the last few weeks - not dissimilar from a rod knock (didn't go away). I presume maybe a small piece of something (sealer/debris?) got stuck in an oil passage perhaps.
It was on the pass side so I popped the cover and pushed each HLA to see if there was any movement (air) and I didn't find ANY to budge at all which was a good thing. I still opted to take the rocker assy off and clean out every single HLA and found that each one was a little sticky and, despite my regular clean synthetic oil everywhere else, they had dark black oil coming out. After putting everything back together the tick is completely gone. This is not an atypical either, many have done this.
Subaru didn't have a hard cutoff of motor design between 96/97 (and other changeovers as well) for specific model years - it was based off of the build date and even then I don't know when that was. Your MY97 could have been built in the summer of 96' and have all the same components as a MY96 EJ22 with HLA just like mine. Best way to tell is to pop the 3 bolts on the pass side cover and check. If you see the adjustment nut and screw slot you know you have SLA and not HLA.
To answer your question, yes SLA can sound quite loud. If many are out of adjustment than it can sound like a sewing machine, if only a few or one than it can mimic a rod knock just like a HLA can. Does yours go away after being warmed up? When was the last time you changed the oil? Having any power loss or HG issues? Do you remember the timeline for which the tick developed? Anything noticeable precede the sound?