The rifle indeed resembles a Bavarian Wallbüchse M1831. In DWJ 1984, 9-12, Martin Behrens wrote a 4-piece article about this special-purpose rifle. The wallrifle was intended to provide the then Bavarian fortresses with a long range (for the day) sniping capability to keep the then current smooth-bore artillery away. The then, 1831, current infantry armament was still a smooth-bore percussion musket with a short effective range. These rifles were originally muzzleloaders with a bore 22.3mm = .878", groove 22.9 mm = .902" diameter, firing patched round balls. Later a Minie-type bullet weighing 100 gramm = 1543 gr was used. Total M1831 production was 825 such rifles. In the mid-1840 the Munich mechanic August Knocke proposed this breechloader to replace the M1831. As you see in the photos, his rifle had a chamber-loading breech action similar to the French wall-rifle M1831. It used a belted round ball like the British Brunswick rifle of 1840. Apparently this Knocke-designed breechloader was never adopted in real numbers, as the rifled muskets then coming into general use had the same ranging capabilities as such wall rifles.
BTW, "Privileg, privilegiert" was used in 18th-19th century Bavaria and Austria instead of "Patent, patentiert". So the breech inscription means "Royal Bavarian patented 1844".