That was my first thought as well, but on a second look, it appears there is quite a dreadful amount of material missing, and I would be concerned with the seal leaking from the outside, not where it seals against the tube. You could try it, but I wouldn't invest any time with the appearance of the lowers until I was sure the seals didn't leak. As has been mentioned, the lowers should be pretty easy to find for cheap or even free since they made so many, so that may be easier. Another point to consider, if you try to salvage the ones you have and they leak, you will likely have sacrificed a set of seals - not an easy thing to remove without damage. Not that expensive, but everything counts when you are an a budget!