Not an issue.
I have had two with lockers and my current one does not.
I think that you will be surprised at how well an unlocked 80 does.
I enjoyed the capability of my double locked rigs, but didn't find too many situations at my build level that required the front locker--It was nice to have but not needed.
These trucks are all at least 14 years old. You WILL have to spend time maintaining the locker actuators--Not a huge deal, but it is one more thing to deal with. I purposefully chose my current rig without lockers for that reason--I didn't have any issues with my previous rigs, but wanted to avoid that headache 5 years from now.
I don't know what your plans are, but regearing with locked axles is much more difficult and expensive than with unlocked--with this comes the issue of twisting the rear shaft when you run 37 inch tires or bigger (some have done it on 35s too) The unlocked axles are not any stronger, it is just that when the rear shaft breaks on the locked axles, it twists the splines by the locker and is then impossible to remove without cutting open the housing with a torch. (may be irrelevant depending on your plans)
I run an aussie locker in the rear of mine--the full time 4wd makes the aussie unoticable during daily driving, even when wet and snowy. It is also cheap and has a great warranty. If you need the front locked, an auto locker is out of the question, so you are pretty much stuck with getting an ARB. You may be able to run a truetrac up front, but that is an unverified rumor.
So, I would focus on finding the rig that has the least miles, best maintenance history, lowest cost and is in the best shape. Lockers only come into play if you find identical trucks and one has lockers.
Hope this helps.
Dan