Mounting Hardware for Interior Deck Lid Panel

[240Znomad]

I have a '71 240Z (4/71 build date) and while replacing the original (deteriorated) cork gasket on the rear deck lid interior panel (vinyl panel over press board held in by 10 fasteners) I noticed that there were two different types of mounting hardware being used as shown in the picture.  About half were the typical plastic rivets while the other half were a captive sheet metal screw and washer that used a u-style spring nut.  I've looked at some of the exploded parts diagrams and it appears that there were a number of different methods used to mount the panel based on the model year.  Does anyone know what the correct method was for a late '71 series car?

[jfa.series1]

My car has this arrangement: four plastic rivets at the outboard corners, six screws inboard - three top and three bottom.

[siteunseen]

here's my attempt at helping/explaining with some measurements and the hardware I used from Lowes.

 

[240Znomad]

When I noticed that there were two different types of hardware used I figured I might as well fix it using all the same so I figured I might as well put it back to it's OE setup.  I'm just not sure what the OE setup was.  I noticed there is a full rear deck lid on Ebay right now with the panel in place and from the pictures it appears that it has the captive sheet metal screw/washer setup that I'm guessing uses the u-style spring nut.

It's interesting that @jfa.series1 also had a mix of hardware (ie. plastic rivets and sheet metal screws) just as mine did but I've got to believe that it didn't come from the factory that way.  

[Patcon]

34 minutes ago, 240Znomad said:

When I noticed that there were two different types of hardware used I figured I might as well fix it using all the same so I figured I might as well put it back to it's OE setup.  I'm just not sure what the OE setup was.  I noticed there is a full rear deck lid on Ebay right now with the panel in place and from the pictures it appears that it has the captive sheet metal screw/washer setup that I'm guessing uses the u-style spring nut.

It's interesting that @jfa.series1 also had a mix of hardware (ie. plastic rivets and sheet metal screws) just as mine did but I've got to believe that it didn't come from the factory that way.  

JFA's (Jims) car is a one owner and I assure you it came that way ?