That buildsheet is authentic.
Arlington did not begin GM A-body production until January 1970.
I have found a few Arlington built Chevelles out there with original buildsheets,but not many.Their coding system was unique,as well as their processing/dating tactics.
Arlington Tx. plant was a brand new facility for the 1970 GM A-bodies,so probably due to workers error,not as many vehicles received them as compared to other assembly plants,but some did receive them.
When these buildsheets are found,they are most likely found underneath the sound deadner that was applied to the floor.Aim for the drivers side floor first,then work your way out and around from there.
It is not unheard of to find these under the seat springs,header fabric and behind door panels etc. too..unless your Dennis Cumby.
