Infinity QB info?

These are circa 1977 or so. A friend was wondering if they are worth anything. No entry in the AG Blue Book, so I'm asking the forum for any info they may have about this model's value in today's market.

Are good sources to check. They are both active sites. I would think there is some sort of market for Quantam series. I know my old reference standards generated interest

Regards, Steelhead
A good/accurate speakers. Needs to be on stands with tweeter at ear level. EMIT tweeter has poor vertical dispersion but great horizontal