RE: Williams peep sight
EDIT;
Whoops, I was wrong. The Williams peep sight mounts onto Benjamin/Sheridan rifles with two holes that are pre-drilled onto the right hand side of the reciever (just behind where the pellet is loaded) and those holes have only been pre-drilled by the factory for the past 8 years.
If your rifle has two empty holes drilled onto the right hand side just behind where the chamber is, you can mount the peep sight. If not, those holes will have to be drilled.
TheWilliams Peep is supposed to work very well with the Sheridan rifles, on theBenjamin 392's they seem to always shoot high even when the adjustments are maxed out.