This is interesting as it is not in Hazlett. The entry in Appendix 6B says "Survivors: None." There were invoices for about 22 of the 3-inch rifled pieces before Noble ceased production due to nasty dispute with the CSA Ordnance Bureau.

The 954 pound weight is not listed in the Appendix 6B so that rules out four of the known (but non-surviving) gun weights.

From Daniel's "Confederate Cannon Foundries" there is the following various info on Noble 3" Iron Rifles:

1. The first battery completed by Noble included three 3" rifles for a local outfit, the Cherokee Artillery of Rome, GA.
2. Other Noble guns went to Cutt's Georgia Battery, Jeff Davis (Alabama) Artillery, and Griffin's (Virginia) Light Artillery. However, the book does not state what types of pieces were supplied for these.
3. On Oct.21st, 1861 a single 3" rifle and a 12 pdr howitzer were loaded on the steamer William Ramsey headed for Calhoun, Georgia and destined for Pensacola, Florida.
4. A few weeks later the Rome Railroad receieved four Noble guns for shipment to Bragg at Pensacola, and six for Hardee in memphis. (It doesn't say what types.)
5. An order for a battery from Noble for the state of Georgia was made in Dec.31, 1861 that included two 3" rifles. These were shipped to Savannah.

Some of the surviving Noble cannon have an "L.J.S." inscription for inspector Capt. L.J. Smith of the CSA Ordnance Dept. If that is not found on your gun then perhaps it means that this particular piece had been ordered by the state of Georgia rather than by the CSA. (That is merely a guess on my part.)

At any rate, it sounds like you have in possession a piece that would be of considerable interest to the recognized authorities on ACW field artillery, since it appears to be the "sole survivor" of its class. I suspect that if you contact them they can make a far better guess as to what unit would have used the weapon based on characteristics of other Noble guns.

Good luck!