MAS 49/56 questions

Hello,

I have an opportunity to buy a MAS 49/56 for $385, but I could probably get the price down a little bit. It is in good shape, however, it is a Century Arms conversion to .308. I have heard mostly that these were very poorly done, but I have also heard that some people are happy with theirs. I have also read that the problem is in the chamber, that they were reamed out badly, but since I now nothing about gunsmithing, if I could get a photo of the chamber, would any of you be able to tell if it was done well or badly? Are there any other potential problems with these that I would need to check out? I have heard that there are sometimes problems with the gas system, so it might be more trouble than its worth for me.

Thanks,
Jim