I did also look down the holes but couldn’t find any sound thing in there at all… What a weird thing for them to leave out
Is there a wire nearby? Both times I had a trim level with missing speakers the wires were run to the hole.
Subarus of that era are a mixed bag when it comes to wiring. If it was a sub harness with the speaker wires (like a separate radio harness) it’s probably not there in a lower trim.
If the speaker wires are in the main dash harness(es) then it could be there but is probably taped back to the bundle somewhere close to the speaker hole.
As an example, My 97 Impreza L had most of the wires for cruise control; the on off switch connector, brake and clutch switch plugs, but not the sub-harness wires for the steering wheel controls.