how do i know if i have a Durango steering box on my jeep or if it is stock?

the previous owner changed it out but i don't know if its a reman stock unit or if it is a durango unit. he welded a reinforcement plate on fender well so i am thinking he may have upgraded to the durango box as well but dont know how to tell for sure. the reason this comes up now is a fellow jeeper with a 98 grand broke his box (the tabs) while on the trail and from what he tells me its a common problem.

 

Measure the large end of the box. If it is 4" you have the heavy duty box. Anything less and you have the standard box.

Where in CA are you. I am in Chico

 

Kinda hard to see but it looks like i have 4" on the big end. Do i have to worry about the tabs breaking off? I am in lancaster BTW, About 2 hours ne of LA.