Telling how much it cost new (assuming it's not really old when inflation would make a big difference) I guess is the only way I'd resolve that. Either that or say I don't remember because I've had it forever.
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Bikes: 1996 Eddy Merckx Titanium EX, 1989/90 Colnago Super(issimo?) Piu(?), 1990 Concorde Aquila(hit by car while riding), others in build queue "when I get the time"