According to the book "Military Rifles of Japan" by Fred Honeycutt, Jr. the general appearance of the rifles in the movie, and what they really used during that period, appear to be Type 13 or Type 18 single shot, bolt action 11 mm modified copies of the French Chassepot with the influence of the Dutch Model 1871 Beaumont. During the beginning of the film the rifled muskets seemed to be Springfield Model 1861/1863, but the rear sites were pronounced and I think that they might be Enfield Model 1855, which the Japanese did initially acquire and later built copies of them.
Having once collected Japanese rifles, I initially expected to see them use the Murata Type 22 rifle, but those came later in 1889. As I have only come across 2 Murata Model 22 rifles over the last 20 years at prices into the thousands of dollars per gun, I doubt that the Type 13/18 in the film were original as they would be very scarce, unless they came across a bunch that had been in storage, however, the cost per unit would be alot to a collector should they be original and available.
The magazine "Military History" did an article on the true story of how the samurai and the progressive military minds did do battle with each other during that period, as the Japanese wanted to modernize from a feudal society to a modern one extremely fast, with the ideas of power and expansion like the European nations.
I hope this helps.
