Welcome to the assyulm.
You have asked what is probably the biggest WI regarding the entire Pacific War, followed fairly closely by Midway WI's (although we have beat then Midway question to death over the last couple of months).
To go with the short version of the answer to your question: No it would NOT have been the same. It would still have been a rather serious drubbing for the USN & USAAF, but JNAF losses would be higher.
How much higher is an open question since the radar, even if it had been wired directly to the Alert klaxon, would only afford about 50 minutes warning (radar contact was established at 07:02 local time, with the attack commencing at approxomately 07:55 hrs). Nevertheless, even 15-20 minutes warning would have allowed for more of the defensive AAA batteries to be manned, ammo to be distributed on at least some of the moored ships, and watertight conditions set across the Harbor. Even 50 minutes isn't sufficient time to scramble all the fighter and attack aircraft on the various airfields, although it would allow time for the "alert" aircraft to reach altitude and perhaps a few other fighters to get into the air.
Now, if the Alert sounds when
USS Ward is initially vectored onto what turned out to be one of the mini-subs (Approx. 03:45 hrs local) or even at 06:30 when the second sighting is called in, things become more difficult for the IJN.
A four hour alert is almost ideal from the American perspective as it allows for fighters to be armed, fueled and launched into defensive positions, bombers, partrol, & attack aircraft to be sent aloft and everything else to be disperised or moved into shelters before the enemy attack. It also allows all defensive sites to be fully manned, for ships to have built up steam to provide power to turrets, rangefinders, and communications independent of shore hook-ups, and to set Battle Station conditions; but NOT enough time for the battleline to attempt to sortie. Any ship that the IJN sank were far better off settling into 40 feet of harbor mud than 5,000 feet of Pacific Ocean. It is not beyond reasonable probabilities that an attack coming with four hours warning would be much closer to the results of the pre-attack IJN wargames; with American losses coming to a couple of battleships and 200 or so aircraft lost or damaged with JNAF losses being around 100 shot down & 100-150 damaged beyond repair.
BTW: It was a flight of B-17s.