Confused about tire variances

I saw this somewhere but could not find it. In laymen's terms, what is the difference between these two tires at TireRack:

BF Goodrich 265/75/16 123Q
BF Goodrich 265/75/16 120/116s

And, at BF Goodrich's site:

LT265/75R16/E123QBSW71887
LT265/75R16/E123SRWL20679

These tires will be mounted on the FJ TRD 6-spoke rims and spend the majority of their time on pavement with some offroading at Gov't Canyon.

 

BSW+black side wall RWL+raised white letter

 

At the BFG site,the 123S actually has more tread depth than the 123Q. Is there some reason for this? Also, is there some load rating I should be looking for in a smoother riding tire? Does this compromise offroad ability?

 

not sure on the tread depth s and q.but the ones u have up there r "e"load range.thats a 10 ply tire.made for heavy haulin.imo thats way to much tire for our trucks.thats a stiff tire along with alot more weight per tire that equals bad fuel economy.i run standard load and have no problem.rides great and alot less fuel loss.

 

http://www.tacomaworld.com/forum/wheels-tires/60620-bfg-load-range.html

 

Looks like they've got different speed ratings. One is the S speed rating(up to 112 mph), the other is Q rated(up to 99 mph). I dont think that those are going to be key parts of making your decision because its a truck after all, I mean who drives a 4x4 truck that fast.
http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=35

 

Are we talking about the BFG A\T KO? If we are....the main difference ( i think) is the black wall version(the 123Q) is made in BAZ(banded at zero) tire construction method. To make a really long explanation short....BFG revised the way they made the internals of the tire so it would ride better and make it more uniform(more round). Hope that answers some of your questions.......good luck