I'd thought I'd share a couple shots that caught my eye.
Felt on the back of the fuel tank hold down strap.
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I'll add a little adhesive so it stays on another 30 years.

Carpet on the top of the fuel tank.
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Even though with every fuel line I remove I get a nice whiff of Varathane. The fuel tank looks really good. But I still think it will a quick Apple Cider Vinegar rinse.
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I'll add a shot of all the felt pads hen I get back out the shop this afternoon.
With measurements. I think Mark and Matt have been talking about making them in some sort of polymer.

Great details.

I recently used apple cider vinegar which turned out to be a mistake.
If you feel that you must do something use red wine vinegar.
Apple cider vinegar contains 'mother' which is orange/brown and indisguishable
from rust.
Also, after using any vinegar you must neutralize the acid. WATER and baking soda are typically suggested. Water on bare metal ? ....not so good.
After chasing flash rust through three cycles and many hours I very reluctantly turned the tank over to a radiator shop for a coating process.
Fingers crossed.
Your tank looks great 'as is'

Thanks for the 2nd opinion. That's what I was thinking too. But I didn't want show my hand.

I chased the same thing on my own tank. Frustrating. I ended up
using the POR 15. Been great for 10 plus years.

My car has the felt pads too, I didn't know they were rare or unusual?

No Perlon on the tank though.......

Probably not. I just hadn't seen them before. Or don't remember
them.

Most or all (i can't remember) of the cars I own and/or parted, have had the felt pads on the tank strap.

None have had the perlon on the tank. thank goodness, that must be a rust accelerator.

That must put me in the cant remember category. LOL.
I think I have 3 sets out for yellow zinc plating. Over restore mode.

My 73 has the felt strap pads too. Never seen the carpet though. Pretty swanky.

To my knowledge they all had felt. My 73 had it.

I think the perlon was an added dealer item, but I've seen it on the early sixes and -4's

My 71 fuel tank hold down straps have the felt on them.

Every car I've seen had them. Certainly not rare when they came with them.

Just another example of the different variations through the years. I have never seen perlon on the top of the tank like that. All the straps I have seen have felt. All the tanks I have pulled have carpet for pads.

I wasn't really thinking the tank strap felt was rare. It just caught my eye. I'm thinking by the time the cars get to me they're gone. LOL. I'll do some measurements today and look for a felt supplier to replace the tattered and missing.

As for the tank pads. I usually see the 2 on the drivers side still in place. On the passenger side they're usually laying in the bottom with 20 years of rust and dirt adhered to them.

All of them have had or had the glue where they fell off.

I recently had the tank boil-out process done commercially, and now know I could have bought a new tank as recently advertised on AA for less money than I paid for the boil!

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Backside fuel tank strap