Your friend is probably pranking. It's not that reservations aren't needed, but it's unlikely that you'd be able to get one. It will be standing-room-only in the books to be sure, and it's pretty much first-come first-served when it comes to seating. Some of the books have VIP sections and some will save a seat or two for their best players, but that's the extent of it.
If you want to try for one, then start thinking about the strategy for getting good seats at a U2 concert. You'll have to show up in the wee hours Sunday morning. But after you get one, you'll also have to guard it till game time. Best is to go with a buddy and nab two seats. That way one can take a break while the other guards both spots. Hang a jacket over the back and put a newspaper and a sign that says "Reserved" in the empty seat.
If you don't want the headache, don't worry. Standing and mingling is good, too. And you can move around from book to book. Along those same lines, there's no reason to be bummed if you weren't invited to one of the private casino "bashes," either. Anthony Curtis says, "Back in the days when I qualified for such things, I was over the moon when I got my first invitation, but I was throwing them in the trash by the time I got my third." These are mostly boring events that you can do without. If you want to watch the "Big Game" in a sports book, staying mobile and "freelancing" is the way to go.