911 Rear seat installation question?

When I bought my car the rear interior was removed to lighten the car. I’m putting it back to it’s original state and had a few quick questions.

What locks the rear seats in the upward position? Is there some sort of clip mechanism in the center where the seat uppers attach? If so, does anyone have a part number for this device? I’ve had a set of vinyl rears just lying around but they don’t have anyway of locking them in the up-right position. I thought about recovering them but I first want to know the answer to this question.

In terms of the large bolts that attach the rear seats to the car… are there any bushings that go between the bolt and the seat?

Thanks for the help in advance.

The rear seats are held up by a short leather strap, one per seat. A good thread in the past described on the construction of these straps. They are available from a parts dealer for about $25.00 each but you can make them for about $2.00.
----------------------
Paul
78SC Targa

OK, I see the straps on the seat but where do they attach? I looked at the rear package tray but I don't see any button attachments.