I would guess it's a low-odds fishery but they do travel past Corvallis for sure. You would be fishing for spring Chinook and summer steelhead most likely if you were going to retain the fish. I scouted Irish Bend once and that looked promising but I never fished there.
Some peeps fished it 40+ years ago. But the runs are wimpy now; at best. And Springers don't run in the Fall. And Summer steel aren't running now either. There's no Fall run that I'm aware of any longer. Which would be on their way to the Mac or upper Willy Forks. IF there are any fish at all.
Incidentally I just pulled out a 6' x 3' map that I have. It was likely created in the 1950's, by the Willamette Steelhead Council. Based upon the extent of the housing developments that I'm very familiar with, for Corvallis. The map goes from the Hwy. 20 entrance into HP--to a bit past the McCartney boat launch off of Peoria Road.
The map has locations marked out for the best waters ONLY for Crappie, Cats, Bass and Sturgeon. So it's rather odd that it was made by a Steelie Club! Probably meaning that even then the Steelie run was about toast--and spots TOTALLY KEPT IN SECRECY.