Let's see: Marlin 39, probably the most commonly used rifle. Also used, in no particular order: Henry Golden Boy, Winchester 9422, Remington 121, and the auto version (can't remember the model no.), Uberti 1866, Marlin slide action (can't remember mo #).
As for sights, Marble tang and Williams/Lyman receiver peeps. Fronts are either the stock posts, or Lyman 17a's. Also a few original Beeches combos.
Have you been to any matches? Probably the easiest route to finding/trying the various guns and sights.