Position of the registered sign

[James Kass]

The REGISTERED SIGN (®) was introduced in 1946 with the Lanham Act. (In 
Section 29.)

Quoting from:
https://bitlaw.com/source/15usc/1111.html
"..., or the letter R enclosed within a circle, thus ®;..."

There was no mention of it being superscripted.  It would be interesting 
to see a scan from the original.  It would surprise me if it appeared in 
the original document as a superscript symbol.

In this PDF from the U. S. Patent and Trademark Office on page 237 (from 
January 1, 2023),
https://www.uspto.gov/sites/default/files/documents/tmlaw.pdf
... the symbol is shown in running text at a normal size and on the 
baseline.

Seems to me that the organization that invented the symbol should be 
considered the authority on its display.