Rob,
On my 62 the rectangular clip looked like a big staple. I had the original engine rebuilt last year and while it was out I decided to detail under the hood. This is what my dust shields looked like. You can just barely make out the clips going across the top and you can see a couple of the holes on the left side where the dust shield has torn away.
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The new dust shields came with heavy wire clips or staples (choose your term) but they are a pain in the the a** to to install. I went to the local big box hardware/lumber yard and got a small role of aluminum wire in the same size as the wire clips. Cut a bunch the same length as what came with the dust shields and used them. My point of view was they bend easily and won't rust. I used a small drill bit in a Dremel and re-drilled the holes and dust shield together.
Unfortunately, I don't have a good photo of the just the inner fender with the new dust shields installed but maybe the following will give you an idea about the out come.
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Here are couple closer shots.
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