1970 is when Porsche began using a ribbed rubber boot collar to hold instruments in the instrument housing panel
In 1989, 911s in the US began to be equipped with a passenger side airbag.
For these classics, one of the upper lid cover attachment bolts is an anchoring point for the support arm brace.
From 1970-1988, 911s had no passenger-side airbag
The support arm brace fastens with 3M® Dual Lock™ tape
There’s some uncertainty as to the specific demarcation date when all vehicles were equipped with a passenger-side airbag and associated lid cover.
For US cars, it was 1989
For German cars, it was 1991
For ROW cars, 1991 may also be the date
There may have been some phasing-in of passenger side airbags --- so it’s important to check your car as to whether it has a passenger-side airbag and lid cover bolt --- BEFORE ordering your PCAR MOUNTS Bracket System ---- don’t just rely on the 1989 model year demarcation date.