"In response to what Jim said about regiments being issued the same type of weapon, usually, there could be a hodge podge of different types of weapons issued within a regiment."

The 1st MO was a Western regiment and arms may not have been available as in the AOP. It is possible that the variety of arms used was due to a problem with supply. This problem would have been more pronounced in early war than late.

In the more regimented and better provided Eastern units, having different makes of arms in a regiment made it a headace for the supply officer to provide ammunition. While there may have been several makes of carbines in use by companies of the same regiment, Uncle Sugar tried to standardize the arms at company level and regimental level simply to standardize ammunition issue.

Also, when determining the type of arms used by a regiment or company the period of the war must be considered. Some regiments/companies started out with one arm and ended the war with something entirely different.

It is a perplexing situation and sometimes there just isn't a definitive answer. If CW arms could talk what a tale they would spin.