Ques. Re: My 1 Cent Benjamin Franklin 1926

Hi, I'm trying to determine if this is a rare Scott 594 or a more common Scott 552. Thanks!

Neither.
A perforation gauge will show this to be 11 x 10.5, which is Scott 632.

Always show the back of the stamp as well. This is the first step to distinguish flat plate and rotary plate stamps.
Scott 632s tend to be lighter green that your stamp, but a perf measurement should go along when posting your stamp image.

To elaborate more on my previous post, while the reverse side is indeed often useful, in this case a comparison of the top/side perforations is conclusive. The size of the stamp is approximately 2cm, the same width of a perforation gauge. When the top and side are aligned at the lower tooth, they differ by 1/2 at the top. The only (non-overprinted) catalog number for this issue featuring a rate differing by half is the perf 11 x 10.5 Scott 632. The shade is also consistent with ths printing.

Thank you both so much for taking the time to reply to my post. Stamps are fascinating, but can also be frustrating to figure out sometimes! I appreciate the great info.