Help with the factory tow package

I have a 2007 Double Cab TRD-OR with the factory tow package. According to the towing bible, this consists of a Class IV receiver, auxiliary oil and tranny coolers, heavy duty alternator/battery,a 7 pin round plug, and plug-n-play connection for a brake controller. I still am left wondering about the receiver.

Every receiver I have ever seen lists a rating for weight-carrying and a separate, higher weight for weight-distributing. My receiver does not have a sticker anywhere with this information and the owner's manual only says 6500lbs towing capacity with a 650lb tongue rating. I also know some class III/IV receivers are not meant to be used with weight-distribution. I can't imagine Toyota would slap a 6500lbs/650lbs rating on and not intend weight distribution to be used, but the info is not there (at least that I can find). So I am left with questions...

1. What "class" receiver is on the tacomas with a factory tow package?
2. Did Toyota not intend a weight-distribution system to be used?
3. Is there a higher rating if weight-distribution is used?

My apologies if this seems dumb to others, but I would appreciate any help. I'm new to the towing world and using this forum has been an incredible help with questions and advice.