Thanks Tom for a great summary. I had my 64 Hummingbird's adjustable bridge (which was a fiasco IMHO) replaced with a plain rosewood bridge with a new bone nut and saddle.
The sound difference was like playing a new guitar. Didn't replace the pins, but may do that someday. I had some other repairs done on her, repair and glue the top cross brace, replaced 4 frets.
The luthiers did a stellar job on the 64 Bird. I've done some recording with her and she does very well.
PS: Why has Gibson reissued the "Early 60s Hummingbird" of late (2011) with an adjustable bridge? I don't get it; why repeat the mistakes of the past? Apparently some don't feel that an adjustable bridge was a mistake.
Huh....