Well spotted Danny!
Desirable though the Tell 3 might be, in those sorts of calibre they would be virtually unusable. So if someone is going to take the trouble to make replacement barrels, perhaps to reclaim relics, why go for calibres that would devalue them so much? It certainly is a puzzle. It might help to know the serial numbers, as if these are consecutive or very close together it could suggest factory experimental models.
Cheers,
John