The camp garden has no proper fence to keep out deer or rabbits.
Around 42 minutes into the film, a boy picks up a rifle from the ashes of a burnt house. Surprisingly enough, the wooden parts of the rifle were spared by the intense fire that burnt the whole place down.
The J.H. Dance was a Confederate copy of the Colt revolver, it was made exclusively for the Confederate Army in 1862, it was not sold to the general public and only 400 were made. The Confederate military had a major shortage of guns, which is why all of these pistols went straight to the Army, it is extremely unlikely that this pistol would be found in an Arizona trade outpost in 1863. Plus the Tracker is shown loading the Dance with cartridges, however it was a cap and ball pistol, it didn't fire cartridges.
There are a number of firearms mistakes throughout the film, mainly dealing with muzzle loading cap and ball revolvers being loaded with cartridges. The first part is supposed to take place in 1859, revolvers back then included the Colt Dragoon, Navy and Walker (which are used in the film), all of which are loaded by pouring gunpowder in the cylinders, crimping a ball (bullet) on top of a patch into the cylinder and putting a firing cap (primer) on the cylinder's nipple. The first cartridge firing revolvers weren't seen until around 1860 but were rare and expensive, they didn't become common enough for the average person to afford until the 1870's. The first affordable, mass produced cartridge firing revolver was the Colt Single Action Army released in 1873. Cartridge conversion kits for the Colt Walker, Army and Navy's seen here didn't come out until 1871.
In the opening scene, the father surveying the land is holding a yellow pencil which was not invented until 30 years later in 1889.
The revolver carried by Hayes Ellison appears to be a Colt Army Model 1860 with a Richard's cartridge conversion kit, which didn't exist at the time. The scenes with Ellison take place in 1863, at that time the Colt Army was strictly a cap and ball pistol, it didn't fire cartridges, which Ellison is shown loading. The Richard's conversion kit allowed the 1860 Army to be converted to fire cartridges, but it didn't come out until 1871.