By the time of the TX Revolution & even more during TWBTS era, smoothbore military firearms of the AWI & Napoleonic War, i.e., the Brown Bess (of its various sorts), the Harpers Ferry muskets, the French Charleville muskets & other European arms of that period were "old, used guns" & were generally about the cheapest serviceable firearms available.
(According to the curator of our Alamo Shrine, fully HALF of all civilian-owned firearms in 1835-45 Texas were Brown Bess muskets.)
For example, in February 1861 when one of the teenaged boys from our family (Richard Henry is thought to have been just past his 14th birthday at that time.) went off to war to defend our tribe against the KS raiders, his father paid 25 cents for a Bess for him to carry to training camp.
(Volunteers were told that if they arrived in camp afoot and/or unarmed that they would be sent home in disgrace. = Many a family sent their soldier off to war with the family's sole horse & firearm.)
Note: An 1862 letter home from Richard indicates that he had acquired a "modern" rifled-musket.
yours, satx