Kim C - I assume you may be interested in re-enactment authenticity? Perhaps another place to look would be in some of the recent findings on banjo history. Their use of gut and then metal strings would probably parallel the guitar's use of same.

Unfortunately I don't have any idea where to find the new research, but there was a thread referencing interesting new findings in banjo history here at mudcat within the past 6 months.

I've been told by a local banjo collector that steel strings and frets became common in about 1870's-80's. He says they were used earlier for one-of-a-kind models, but were too expensive to be manufactured widely for mass consumption.