Just $75 more than a Cimarron what? The Cimarron 1851 should be $270 retail max.
I have lots of Cimarron and Uberti 51s, 61s and 60s as well as both second gen Colt 1851 and 1860. I have a signature series 1860 that came out of the box with a loose cylinder pin ande a very early bolt drop, marking the cylinder fairly quickly.
The second gen Colts have a very good finish and assembly, the parts fit and were smoothed well before they were buffed, so there are no rounded corners or wavy surfaces. The second gen guns are also very authentic in shapes and details. The color case is beautiful, and real, and the bluing and plating, if done are right.
The third generation Signature Series CAN be well fit and finished, but as often as not, are not. Parts like the triggerguard are often polished separately from the frame, so the corners are rounded, not flush, and the octagonal barrels are overbuffed so the edges are rounded and the flats are wavy. And details are off, like the size of a Navy triggerguard. The plating is nickel, not silver, details might be missing like the capping groove, and other assorted details. The color case is, however very good, and real.
All this means you should personally check the gun out, and not buy it mailorder blind.