How do you know if you have a rear TSB done

I've been trying to read through all these different threads about people getting the rear TSB done but no one ever says what it is. I bought my truck used about 4 months ago and i know its not under warranty anymore due to miles. Is there something that i can look at that will definitively let me know if the TSB was done?

 

If there are 4 leafs in the spring pack then you have had the TSB done or someone added a leaf. If it's a non TRD Truck but has the Billstein shocks and 4 leafs it's had the TSB done.

 

Dammit. I only have three back there. I keep seeing post about people adding a leaf when doing a lift. If i only have 2 leafs does that mean that i need to add two leafs on each side?

 

You have three leafs on each side (two spring + 1 overload). You would need to add a single leaf on each side.

However, aftermarket leafs that add lift will NOT add load capacity like the TSB springs will. Load carrying capacity is affected by leaf spring's spring rate. Spring rate on aftermarket AALs is more designed for articulation/flex rather than load carrying.

Also: Not to be a dick but you should be more patient and read the stuff you search. All of this has been covered a million times. I'm not indulging any more.