Still having a hard time wrapping my mind around what you're saying.
I don't know what you mean by 'duplicate signs popping up'. If you're talking original authentic petroliana, those signs were obviously already in circulation. The fact you didn't see it in someone else's collection hanging on the wall is irrelevant. Maybe ignorance is bliss ... just because you didn't know Joe had one hanging on his wall shouldn't change your perception of your own sign.
The fact they are being sold again by another auction house shouldn't significantly change the scarcity or value of yours ... if anything in this current cycle it should drive the value of your sign up ... not down.
If by 'duplicate signs popping up' you mean repops ... I don't even think about their impact on the hobby as it can't be controlled anyway.
