Lame? No. Totally necessary? Not really.
Most schools will supply you with the basics (gloves and helmets). While the idea of putting on a helmet someone else has sweated in might skeeve you out, look at the flipside: do you really want to funk up YOUR brand new lid you just dropped a few hundred $$$ on? It's a toss up. You can always get a dri-fit skullcap (to act as a barrier between you and the loaner helmet), take your own lid with you to the class, and see what kind of condition their stuff is in.
Gloves, yeah, if you've got a pair that are already broken in (you DON'T wanna try to spend 2 12-hour days in NEW gloves... your hands will hurt if they're not broken in), then you might be more comfy in your own.
Jacket? Not really necessary. Bear in mind the speeds you'll be travelling at -- VERY low speeds. And much of the day you won't be moving at ALL... you'll be standing still, or sitting and waiting. So if you've got a meshie jacket, then you might be fine. But if you're in textile or leather? You'll be uncomfortably hot.
Just wear what you're comfortable in. The class is long, exhausting, but a ton of fun. So just make sure you're comfortable, wearing light colored, breathable fabrics, and enjoy yourself!