Yes Narrandera inland fisheries centre is open to the public.
It is only open on weekdays though, and I think they charge about $5 per person for a tour. I am a Fishcare Volunteer and do about 5 kids fishing clinics there each year, as well as going there for meetings, training and other things. Our boss in NSW fisheries was working on allowing us Fishcare Volunteers to open the place and do tours on weekends during school holidays or long weekends.
We have a couple of kids fishing clinics there at the start of the next school holidays.