I need several metal body "plugs" for my '74 Barracuda. I don't know where mine went to, they must have been tossed out by the body shop. These are different than the typical rubber body plugs, these have sort of teeth on one side, and they slip into the hole, and then there's a tab on the front for a screw to retain it. They're located in the passenger compartment floor area. I checked with Year One, they only sell these in complete kits for $100+, which I don't need. Any ideas? Thanks.

which size?
http://amhightechauto.com/images/parts/sbp15.jpg