Hi Fred,
No grade 1 indicator is needed before the superscript indicator because grade 1 mode is already in effect with the numeric indicator before the 3. The right parenthesis terminates numeric mode but not grade 1 mode, which is terminated by a space, hyphen, dash, or grade 1 terminator. (UEB 6.5.1, also 6.5.2)
The superscript 4 will need a numeric indicator before it since numeric mode has been terminated at the right parenthesis.
Braille on,
Julie