The musket is a M1812 type 1. The rear facing barrel band springs are a dead give away. Production for the type 1 was limited to 1815, and of the 8 primary variations of the M1812 (yes there are 8!) the type 1 is one of the more uncommon varieties.
The Standard Model of 1812 was developed by M.T. Wickham. Several prototypes were produced at Harpers Ferry in 1812-13 and sent to the Springfield Arsenal for production. The War of 1812 prevented the re-gearing of the armory to produce the 1812, and production of the 1795 type muskets continued into 1814. Some 1795 type muskets were probably produced in 1815, and the exact switchover sate to the M1812 is unknown.
The earliest M1812 muskets (such as yours) were built with some leftover components of the 1795 muskets, including trigger guards, barrel bands and band springs. Production was discontinued in 1815 and Type 2 production began.
Proper M1812 muskets (the type 2) are identified by their short, stubby "stud bands" developed by M.T. Wickham, and a front band that somewhat resembles the bands of M1835/40 and M1842 muskets. Production of the type 2 was discontinued in 1816. Concurrent with the production of M1812 type 2 two other variations were produced; one variety with a reshaped 1813 dated 1795 type lock, and another that was slightly shorter that the standard 42" barrel muskets. The shorter muskets are referred to as "Special Purpose Muskets" by collectors, as it is unclear what their intended use was for. It is unknown how many of each variety were produced, however production records for 1816 are available and feature these 3 types of muskets.
Towards the 3rd quarter of 1816 band springs were changed to conventional long band forward facing springs, in accordance with the new M1816 design. The stock configuration with the high comb and recessed cheek rest was likewise dismissed in 1816 and replaced with a stock that looks much more like a standard M1816 stock. These would represent variations 5 and 6.
In 1817 the lock markings and barrel proofings were changed. Some muskets were produced with an convex arched SPRINGFIELD behind the hammer, as seen on some early 1795 type muskets. Another variant was produced with M1816 style lock markings, abet on a flat, beveled edged M1812 lock. Final production of M1812 muskets concluded in the early days of 1818, and the model was supplanted with the M1816 musket series (M1816, 1822, 1828).
American Military Shoulder Arms, Vol. 2 has some excellent information on this musket series, as they are generally misunderstood by collectors, and either lumped in with the 1795 type muskets, or M1816 series. However, they are the first regulation American made pattern arm produced at the National armories (the 1795 muskets being direct copies of M1763/66 French muskets).
Cheers,
Garrett