Hi Keith
Yes, exactly. What would you call a Griffen gun other than a Griffen gun? It has some appearance of the M1861 3" Ordnance gun in the tube except the breech has little in common with the Ordnance rifle. Breech has a casabel and a squared rim base, Ordnance does not. Breech looks more like that of a M1841 6 pounder. Little used because it was overweight. At best, these can be called a test batch of 18 tubes. Only 9 survive.
Ron