this was a while back but i blown my head gaskets and wondering when this happens will it mess up the o2's or cats the car was parked soon as hg's went
I have changed headgaskets on three SCs and haven't had to change O2 sensors. On my 89 SC the O2s only had 3000 miles on them so I didn't change them when the HG blew. That was in 2003 and O2s still working fine as I got 25.3 MPG on the trip to the Shootout. If you don't get any codes afterwads I would say they are okay.
I didn't change my O2 sensors after my head gasket job either. I took them out and cleaned them with electrical parts cleaner, and then cut off the cats and had new downtubes made and re-used the sensors. I'm sure they could be replaced and I might see better gas mileage, but I have no codes.