U+00AE ® REGISTERED SIGN is a different character from U+24C7 Ⓡ CIRCLED LATIN CAPITAL LETTER R as many fonts draw the registered trademark symbol smaller and possibly superscripted.
While some fonts may be doing this, others are clearly not, so it seems like it is acceptable to re-use the Enclosed Alphanumerics for now.
Example for another (brand-name) font using the same sizes for the characters:
Add
According to https://en.wikipedia.org/wiki/Registered_trademark_symbol#Related_and_similar_symbols,
While some fonts may be doing this, others are clearly not, so it seems like it is acceptable to re-use the Enclosed Alphanumerics for now.
Example for another (brand-name) font using the same sizes for the characters: