In all honesty you should give it a shot yourself. If you put it together yourself or as much as you can you will better understand how it works. Then if you ever have to replace or swap something you know how to take it apart.
If you are talking about building out a stripped lower its easy and all you need are some roll pin punches, a lightweight hammer, a stock wrench, and a razor blade or some other thin object to help with getting the detents in.
check out this link. It has easy step by step instructions on how to build an entire rifle. I used it as a reference when i built my lower and it was pretty easy. just a hint though. It may be helpful to work with the lower inside a box or a bag when messing with the detents and detent springs to keep them from shooting across the room if your hand slips.
As they said a lower is pretty easy and will give you a nice understanding of its functioning. That being said though, we can assemble both the lower and upper for you.