The pistol in the Dixie ad is an Italian dream pistol**.
It is based on a Colt 1851 Navy but it is in the wrong caliber. The Colt 1851 was never made in a .44 caliber.
Basically, the Colt Navy was a .36 caliber revolver first sold in 1851.
The Colt Army was a .44 caliber revolver first sold in 1862.
To help you identify the Colt pistols here is a brief listing:
1847 Walker: Very large 6 shot, .44 cal gun that weighs over 4 pounds unloaded.
It has a round barrel with a partial octagon shape at the breech. The loading lever does not have the later style latch and is held up by a spring.
1849 Pocket Pistol: A small 5 shot, .31 caliber revolver with an octagon barrel. Its loading lever is held up by a latch at the front.
1851 Colt Navy: The most popular model, a 6 shot, .36 caliber revolver with an octagon barrel. Its loading lever is held up by a latch at the front.
1860 Colt Army: A 6 shot, .44 caliber revolver with a round "streamlined" barrel. It uses a streamlined loading lever which "creeps" along the bottom of the barrel using pointed teeth to move the ram. The loading lever is held up by a catch at the front.
This was the first Colt with a "stepped" or "rebated" cylinder and the corresponding relief in the frame, the step being necessary to allow clearance for its larger .44 caliber cylinder.
1861 Colt Navy: The .36 caliber replacement for the Colt 1851 Navy. Like the 1860 Army, it has a round streamlined barrel and the creeping style loading lever. The cylinder is not stepped like the larger .44 cal Army.
There are several other Colt pistols but these are the most common of the modern reproductions.
** The .44 caliber Navy was dreamed up by the Italians. Someone figured that by using a stepped cylinder they could sell the Navy style pistols to folks who wanted the bigger caliber.
Although it is not historically correct, it is a real fun gun to own and to shoot.
The first cap & ball revolver I bought was a steel framed .44 caliber "Navy" and it was great.
Later on, I got a "I only want to own historically accurate pistols mindset" so I sold my .44 Navy.
After selling it I regretted my move.
The very slight differences in the grip between the 1851 "Navy" and the later 1860 Army made the feel of the "Navy" much more to my liking and its .44 caliber spoke with a resounding BOOM when she went off.