Dennis,
I tried this method also on the latest gun I'm working on, and am quite happy with the result.
It turned out at least as good as most of the guns that I have made using the more common disassembly method.
My reason for doing it was simply that I never really enjoyed the lock inletting process the other way, and was looking for a better alternative. It seems less tedious to me and I will likely use this method in the future. Positioning the lock to begin the process may be a bit tricky, but after that, I found the inletting of the internals easier, and probably more precise than my usual result.
Oh by the way, the first person who ever suggested this method to me was Jack Brooks, quite a few years back. I'd be happy if my work was anywhere close to the quality of his.
Jeff