Most likely a third-generation star. Hard to imagine a first-generation star consisting mostly of H and He manufacturing enough heavier elements to complete the Periodic Table and give us our terrestrial composition...an issue which speaks to the heart of this debate.
No matter how intelligent and dexterious the life-form, without sufficient raw materials, they're not going into space. Thus, a metallic-rich planet orbiting a third-generation star may be essential. If this is so, then perhaps all life in Universe is at about the same stage of development that we are...with interstellar space travel as yet impossible.
More than likely, however, a second generation star is not out of the question.
This is just one site of many that postulates either: :-)
http://www.rwc.uc.edu/koehler/biophys/7b.html
I do agree with your assessment. We just don't have enough data to make an informed proclamation about ET and/or ET exploration.