I don't know enough about those early bezels to comment, maybe freddy knows more since that's his area of study these days. Skeet and Urul mention the early bezel was also plastic, covered with a metal-like substance. As Tomvox states, the original bezel is in poor condition, with an Italian insert.
I do have my doubts about the dial though. A 1958 dial would be marked 'Swiss' at the bottom, I believe, since tritium didn't come into use until around 1963 or so. Nevertheless, I'd figure this dial as an early 60's replacement, when gilt was still prevalent.