Hello there
I think you are going to need to get a little creative.
The old FWC's were different than the modern day FWC's.
The old Fleet Models were usually bolted down to the truck bed.
(you can probably see the original holes in your camper floor still)
We will typically NOT bolt an FWC on the 2005 - 2010 Toyota Tacoma trucks in fear that the camper bolts will rip through Toyota composite (plastic) truck bed.
We either use Tork-Lift external tie downs, or we normally use custom internal steel brackets that bolt to the truck bed.
BUT, the modern day steel custom brackets we use won't help you because the older four wheel campers usually did not have any eye nuts in the camper base or any access ports holes for access to the truck bed for attaching internal turn buckles.
Maybe the easiest way would be installing some eye nuts / eye bolts in the edges of the camper bought and using external tie downs.
You might want to look at this thread ...
http://www.wanderthewest.com/forum/index.php?/topic/3557/
It might not be what you want to hear, but I hope it helps gives you a better idea on what your next steps will need to be.
Happy Camping !
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