Jim, I'm not 100% sure on this but I believe it was just on 70's non-rally. it is actually there to hold the lower dash pad in place with two mounting screws that screw into this bracket. Maybe someone with more knowledge about 68-69 b-bodys can shed some light on this, but I do know the lower dash assembly was completly different in 70, Hope this helps.

70RT, I have tons of pictures of 70 non rally dash pics from my Coronet RT if you need them. let me know, I'm actually in the process of reassembling mine now after restoring each component.

Scott