Yes, the Hilton Lake Buena Vista is a different hotel. I've stayed at all of the Hiltons you're referencing.
In the past 5 years, I've stayed at least 40 nights at the Hilton Lake Buena Vista. It's not a great hotel. The staff is disinterested and I always had at least one problem on every stay. Some problems were minor. However, on other trips I had a broken toilet that took over an hour and 3 phone calls to get someone to the room to fix. And on two different trips, I was woken by groundskeepers using leaf blowers near the guest rooms prior to 7am. The response when I complained about that was like "that's when they come, there's nothing we can do about it."
Now, I only stay at the Hilton Lake Buena Vista if it's dirt cheap. My definition of dirt cheap for that hotel would be around $110 or less, including resort fee.
On Hilton points, go with the Hilton Bonnet Creek. It's a much better hotel in a more tranquil setting. (Most rooms there have nice views. At the Hilton Lake Buena Vista, about 40% of the room directly face Interstate 4.) The pool at the Hilton Bonnet Creek is great, if water is your thing.
If you're planning on using the theme park shuttles at the Hilton Bonnet Creek, make sure to check the frequency. It's generally once per hour with gaps in the afternoon where it's 2 or even 3 hours between shuttles. They publish the schedule online, but it's usually only for the current week. Still, it will give you an idea of how it works.
http://www.bonnetshuttle.com/
