The sill plates are the same for 67-69 and the originals would have the rivets.
The ones sold in the auction for $394.50 are the GM replacement plates and did not have the rivets. These sill plates, part number 7644760 are still available from GM at $50.00 a piece and also do not have rivets. Unless there is a huge difference between them I don't get it.
Rick H.