A database just spit out this result from my using a search term looking for something quite different. I have such mixed emotions. This should be in a museum, not a private collection. I’ve been to Kolophon. I’ve seen the holes created by speculative digging among the ruins. I’ve seen the primarily subsistence level agriculture of the current community. I know why this is on the collector’s market. It just doesn’t belong to any one of us; it belongs to all of us. It is not a mass produced object.
Anyway. I’m still glad that we have photos and details regarding its weight and other features and that I get to see it.
The catalogue say: “Here, ΛΕΙΤΡΑ is the Greek translation for LIBRA in Latin and with a weight of 348 g, it corresponds fairly well to the Roman pound of 327 g. Approx.”
I would point out that oxidation can effect the weight of lead objects in particular, especially when were just talking a matter of grams.
Here’s another earlier post on the weight of the Roman pound.
Here is newer bibliography: Butcher and Ponting 2015: 206-208.