The 335 was at lower end of the Anschutz line, a pretty basic sporting rifle not to different from the FWB 124. Power rating was 700 fps in .177, but there was apparently a couple different springs offered for different power levels. They are pretty accurate, but recoil hard. These were made for some number of years, from the 1980s to 2003. Generally a decent 335 will sell for around $200 or less depending on condition. Here in the US the 335 was sold for a while as the Crosman Challenger 6500. A new in box 6500 sold recently for $232.
There are plenty of scopes that will work on that gun. Leupold 3-9x33EFR, Simmons 44 mag, a couple Bushnells, Swifts, etc