Yes you need to drill. Put the top on, mark holes, remove top, then drill. Maybe you can drill with it on there, but I couldn't because of my roll cage.
Everything held up fine for about 4 yrs of on/off. Then the holes started stripping. I made a thin plate that sandwiches the windshield frame. I think you can buy these, but I made mine.
1977 CJ-7 with Ford 302 engine
2.5 inch springs Matkins Frame with 1.5 inch body lift and all Fiberglass body D30/M20 w/3.54 gears, Moser 1-piece and Rear Aussie Locker, Jeep T-18w/Dana 20 and 35" tires Dual Flowmaster Exhaust, 6 point roll cage, OBA and a bunch of other stuff.