The Anschutz 250 is NOT a "copy" of any FWB design. And is most definitely not "junk."
Anschutz actually invented the fixed-barrel, sliding-breech, sidelever-cocking, recoil-suppressed target air rifle. Their model 220 (1960) was a quantum leap over the best match guns of the day - the barrel-cocking, recoiling Walther LG 55 and Weihrauch HW 55 - and sent their competitors into panic mode. The 220 tamed recoil with an internal pneumatic damper; the model 250 (1968) was an evolved version with a hydraulic damper. The 250 sold well, was made for several years, and has three different variations (the OP's magazine pics show the first variant).
FWB's first target rifle was the model 150 (1963). Its sledge-type recoil control works in a completely different way from the Anschutz, and the patents for these designs in no way overlap. (Diana's first Giss double-piston rifle - only truly recoilless springer system - was the barrel-cocking model 60, which also came out in 1963.)
Anschutz's system could better be described as recoil suppression, rather than elimination. The rear of the spring sits on a plunger in front of a tiny piston, which moves a short distance through the damper when fired, taming the rearward shove of the spring. I've shot both the 220 and 250, and they are unique - no movement when the trigger breaks, but a weird little "shiver" of spring vibration a split-second later. They are extremely accurate, well-made, and beautifully finished, with some of the best wood finish and checkering you'll ever see on a factory airgun. The triggers are excellent and of course Anschutz match sights are second to none. The FWB's did dominate top-level competition in those days...helped along by well-placed advertising and sponsorship money...but the Anschutz rifles held their own.
Yes, you want to be extra careful buying a 250, as the seals in the dampers can definitely cause issues. But the various plastic seals and bumpers in the FWB, Diana, and Walther match rifles of the 1960's were short-lived, too. And when those go bad, we replace them with improved modern materials - we don't throw the guns away, LOL...! I would suggest Anschutz is worthy of the same respect.