There was a Roy Moore who graduated in 1977: https://www.allhighschools.com/alumni-search/southside-high-school/roy-moore/5083198
This may be the Roy who signed her yearbook.
She is in class of 1979: https://www.allhighschools.com/alumni-search/southside-high-school/bev-young/5082985
WOW - amazing fact if true!!!!!!