If you go back to ch 210, the band artwork is there. Ch 226 little Mo is looking at a guitar and HeTian notices, setting the seed.
The author has been doing some serious signposting the whole story.
EDIT; Wasn't Jian Yi kidnapped in the first few weeks of highschool and just disappeared?
Check out the Christmas specials set in "the present" (grown up Mo and Tian ch 271.5), Mo is wearing the black studs and has an additional ring in his ear........ I think about its meaning waaaay too much.