Was This 1920 Franklin Green 1 Cent A Scott #544?

No.
Your stamp is postmarked in 1920. 544 is not known until late 1922.

You can rule out 544 by the postmark which is dated 1920. 544 was issued in 1922.

John and I were typing concurrently I see.

Would it be a Scott #423D?

No. It seems as if you are hunting for high value catalog numbers and trying to assign your stamp to those. This is a backwards approach. First you need to determine the perforation rate(s) of your stamp. Assume that you have a common variety because that is the most likely outcome.

So, step one = Perforation Rate

Let us know what you find, and we can walk you through more steps if necessary.

If Perf 11 my guess would be you have a 498.

Always assume you have the most-common possibility, and start eliminating from there.

It's realistic, and it's a lot more efficient with your time. When you do the basic blocking and tackling, you'll systematize your identification, and you'll increase the chance that you find the stamps that are a bit out of the ordinary. And you never know, you might hit the jackpot. It happens, but not often. If you put in the work with a system, you increase your chances.

My 2d.

Thanks for all of your valuable opinions & suggestions!