Could be, hard to tell just looking at a picture. With all the replicas around you need to give it to an expert to check. If you can take a look at it, take a look at the bore; very few replicas were made with progressive twist like the originals.
An original Remington 1858 with original finish (not reblued, which would decrease the value) was going on for around 2200-2800 $ last I looked for one in Europe, in solid to good shape (online, the closest one for sale is two days of driving away).