Phil - The Euroarms version of the 1858 Remington New Army is really, with one exception, a replica of the first version of that model, the Remington-Beals Army Model. The discriminating feature is the lack of frame relief at the cylinder/barrel interface - note that there are no barrel threads showing in front of the cylinder. This model exhibits the well known Remington New Army tendency to bind up even more than the later 1858 Remington New Army does.
The exception mentioned above is the hammer safety notches on the back of the cylinder - the original Remington-Beals Army Model did not have those notches.
Here's my example, manufactured in 1972: