I don't think you can assume that from not getting an answer... knowing this forum, if someone actually knows for sure they're cheap imitations they'll tell you so. No answer usually means they can't tell? Maybe the right person hasn't looked at it - give it a bit of time.
I'm more into post-1945 German mid century modern-style glass vases myself, which means I know nothing about lamp bases and pieces that are pre-war or imitating the pre-war look, so I'm afraid I can't help you along...
Astrid