Okay, so finding a cached version of his followed list is impossible unless you already have the cache of it on your system (because Twitter is stupid >.>). But using the WaybackMachine I found out that at the time of December of 2017, Matt only followed 480 people. It doesn't tell us much, but that does mean that he followed Sakurai this year. And more than likely, he followed him within the past couple months, if not weeks (or days if you want to put on your tinfoil hat owo). There's real way to tell exactly when he followed him, only that it was pretty recently.