If you intend to go to the top of Whitney, you must have the right permit, and I'm sorry that you made some poor assumptions. I don't think that there are any Mount Whitney guidebooks that are misleading in this regard, and the Forest Service web site has current information.
Back in the old days when I started (in the 1970's), permits were required, but they were do-it-yourself permits that just allowed the Forest Service to keep statistics on trail use. The whole permit system kept getting more and more complex as trail use increased, and especially as illegal trail use increased. Now there is a standard chokepoint along the trail just above Lone Pine Lake where the rangers check permits in the early morning.
Now, for people who have applied for their permits and got a confirmation, they have to actually pick up the permits on the day before. If they don't show, or if they have not called to say they are late, the Forest Service will throw those permits up for grabs. However, if you are not standing in line at the permit office, that won't do much for you. Apparently a few people score their permits that way, but it is an awfully shakey way to plan.
It's getting so bad with me that when I walk up to the permit desk, they look at me and alert the other permit workers, "Hey, look, it's the old guy!"