Yeah that's the one. I took pics a while ago but not sure I can find them. I'm sure the rangers know of it and would have intentionally collapsed it if they thought it was unsafe. Seems very un-California like to not stop the public from injuring themselves.
From my untrained eye it appears to just be sand and not actual sandstone. I went all the way back once to just say I did it but probably wouldn't go inside again unless I knew it was safe.