Weaver is owned by Vista Outdoors
http://weaveroptics.com/general/about_us/. From memory, Leupold bought Redfield.
These days I steer away from second hand Leupolds (and any other top line maker) due to the huge number of fakes in circulation. Some of these are so identical externally that even Leupold can't tell the difference without checking the serial number. Of course the difference is build quality inside the scope. Several of the clones have reasonable optics in good light. They lose out in poor light conditions and probably won't hold up to recoil.
For me its better to save up and buy new from a legit dealer. Sure it costs more, but you know you're getting quality that'll last and that's supported by the manufacturer.