[bmcgilvray]

I don't know on that date...but...

On the right side, they have the 'New Navy' DA Revolver represented twice ( instead of maybe having the 'New Navy' and, the 'New Army' being each shown once ).

Otherwise, the year "1856" does not correspond to anything I know of.

The New Navy had only been out a couple of years. It must have been considered pretty innovative and progressive, being a side-swing double-action revolver with simultaneous ejection. Perhaps Colt thought so. Maybe they were using the pair of illustrations to show off the features of their newest design.