This is a very nice example of an early Vienna horn design and closely resembles the wrap attributed to Joseph Riedl.   Riedl's Vienna horn wrap of 1830 was very symetrical in design of the valve slides, as is this model by an anonymous maker and the Cidrich Vienna horn in this collection. 

The date of manufacture is estimated to be ca. 1840 based on the relatively small bore, the large "zipper" seams in the tubing throughout, the similarity to the Riedl horns and other stylistic characteristics. It is in "Old Austrian High Pitch," a'= 460.8 Hz.) with an F-crook (110 cm.) which was common in Austro-Hungarian Imperial and Royal ("K.u.K.") military and civilian bands.  It can be lowered to modern standard pitch (a' = 440 Hz.) with an E crook (136 cm.).

A most unusual aspect of this horn is that it is built to be played using the right hand to operate the valves with the bell facing left.  This is opposite to the standard orientation and is very uncommon. In most cases horns have been configured this way to accommodate an individual player who, because of some disability, is unable to use the left hand for the valves. The collection of the Metropolitan Museum of Art includes a right-handed horn. An early nineteenth century horn tutor by Franz Joseph Fröhlich (1780-1862) describes the left- and right-hand holding in reference to playing duos with bells facing toward each other instead of pointing in the same direction.

The above view is actually the front (i.e. audience side) of the horn and the player's side is shown below.  Note that the valve levers are on the near side in the above photo.  Normally they would be to be on the opposite side of the  horn and fingered with the left hand.  Compare this with the very similar Cidrich horn.

The illustration below accompanied the application for a fifteen year Privilegium of Leopold Uhlmann (Nr. 2053, issued July 12, 1830, Vienna) for his improvement to the Kail/Riedl "Vienna Pumpen" valve. It shows the valve levers placed as if for right-handed use, and on the same side as the leadpipe.

    
(Heyde, 1987, p.298)

Invention of the double-piston "Wiener pumpen" valve is attributed to Joseph Kail and Joseph Riedl, both of Vienna, in 1823.  It is based on the original Stoelzel valve and as such has the bottom of the pistons open as a port to the valve slide.  When at rest the pistons inside the valve casings (right) allow the resonating air column to pass through the upper ports and  bypass the valve slides.  When the player depresses the valve lever the pistons are pushed up which opens the air column to the valve slide through the lower ports.

The bell flare has a garland or "kranz" around the edge, a metal ring that prevents the sound from becoming too brassy or "edging out" at higher volumes.   In this case it is highly decorated with beautifully engraved ornate flowers, leaves and acorns.

Details such as the bell garland decoration (above),  the four-pointed star shape bell brace plate (right) and the crook receiver (below) might assist in identifying the maker of this horn.