I say its not an officer's musket... it is nowhere near of good enough quality. (This term is grossly overused. Real officers muskets are actually quite rare and always of much better than "munitions" quality. They can easily be confused with very high grade volunteer muskets, but this is not one of those.) Its a standard export grade light musket, post 1813. The KW&A stands for Ketland, Walker and Adams which places it in a fairly narrow time frame as shortly after John Adams was taken into the partnership, William Walker retired. It was probably made in 1814 or 1815.
This sort of musket was listed in the Ketland wholesale price list as "muskets with bayonet, steel rods" They were a B'ham staple product and I doubt very much anyone named Ketland had anything to do with their manufacture beyond paying the bill when they arrived.
As far as the two K firms are concerned... T. Ketland was Thomas Sr. For most of his career he had a partner named William Walker who was probably the "money man" in the export business. Walker's name rarely appears on the guns and then only at the very end although he was involved at least as early as 1785. He never referred to himself as a gunmaker or gunsmith... he was always a "merchant" which, in 18th century B'ham trade, meant that he traded overseas. John Adams was TK Sr's brother-in-law, married to TK's much younger half-sister.
W. Ketland was TK's oldest son and the only son to be a partner in the TK firm. He left the company in 1801 to set up on his own but died in 1804. His company continued on until bankrupt in 1831.