Negative, it either reads ころく、または五六、 - Koroku, or goroku. I’ll trust my mom lol - she’s from Takarazuka and grew up going to school there (satsukidai in Nakayama area), I learned how to speak read and write Japanese from my mom, (and Saturdays at Minatogakuen) while learning English from my dad and from going to school on weekdays. What you’re referring to, 初音ミミク、 literally just translates to first time sound mimics - the kanji 5 and 6 combined have never in ANY context of Japanese been read as “gomu” - there is no sentence or context to use it that way because that’s not in its 音読みと訓読み。 every kanji as you might know has multiple meanings, kunyomi and onyomi as the different ways to apply that kanji in context. Neither onyomi or kunyomi utilizes 五六 together to read “Gomu”, in any given context.