Based on advice from the other leaf spring TSB threads on here, I called up the Toyota 800 number (800-331-4331) and told the lady my Tacoma was bottoming out, the ride was rough when I carry a heavy load, etc. Gave her my VIN and she said there was no TSB applicable to my truck. Great.
So I head on over to my dealer to get maintenance done and had the TSB in hand. Went to the service rep, handed him the paper and said I'd like to get that done. He looked it over, checked out the numbers on my truck and said he'd order the parts today. Easy as that. Interestingly enough, he said that's the first he ever heard of this TSB. Got it scheduled for next Tuesday.