It's entirely possible that the Colt was made for the patent was filed for and granted. Colt applied for a British patent for his revolver in 1835 and filed in American for the same invention on February 25, 1836. However, he made his first revolving gun March 5th, 1836. The Alamo fell March 6th, 1836. So the Supernatural lore holds.
This is the original comment as posted: John says that the Colt was forged underneath Haley's Comet on the night the Alamo fell. Haley's Comet appeared on November 16, 1835, the battle for the Alamo began on February 23, 1836 and ended on March 6, 1836. Furthermore, if going by the date of the comet, Colt's revolver would not have even been invented yet, as he first applied for the patent on February 25, 1836.
This is the original comment as posted: John says that the Colt was forged underneath Haley's Comet on the night the Alamo fell. Haley's Comet appeared on November 16, 1835, the battle for the Alamo began on February 23, 1836 and ended on March 6, 1836. Furthermore, if going by the date of the comet, Colt's revolver would not have even been invented yet, as he first applied for the patent on February 25, 1836.
The name of the man killed by vampires is Daniel ELKINS, which is repeated numerous times during the show. Yet when Dean and Sam find the man's address in John Winchester's journal, the listing says D. ELKIN.