OK, I'm with you. There are two top plate configurations. The graphite top plate that comes with the TRF car doesn't need the aluminum bar for the shock to attach to, since it's built in. The FRP upper decks require this. I guess it's because they flex too much. When I converted my TRF car from the LM type chassis to the F type chassis, I only replaced the chassis. I did not change the upper deck. I converted it to the side antenna mount, but that is not a requirement.
This is what the TRF car comes with
This is what the top deck that the F103RS/RX come with looks like. This is actually the CF version of the stock upper deck.
The long FRP upper deck looks like this.
The blue part in this picture is what you need to mount the shock on the long and short FRP decks and the CF version of the short upper deck. Of course, the stock piece is silver.
I hope that clears it up. I'll take some pictures of my car when I get home so you can see how mine is set up.