Sometimes, companies like Cimarron or Navy Arms demand different specs (better fit and finish) or even rework the basic gun (Cimarron Evil Roy revolvers, for example).
However, I believe that the Uberti-branded guns are every bit as nice as the Uberti-made but other-branded guns, in the case of the 1873 rifles. Uberti makes quality guns, though my low-end Uberti-brand SAA would need trigger work to be top-notch. So does a real Colt, though. Their 1873 rifles are beautiful out of the box.
There's little price difference, in your post, though. I'd be tempted to go with convenience, availability and customer service.
Question: are you going to engrave the frame? If so, casehardened might not be the top choice.
BTW if you don't mind an 1892 (I know it's a different canvas for engraving) the Puma guns are damned nice, and for half the price you're talking about.
http://www.legacysports.com/ They make stainless/octagon, if that floats your boat style-wise.
I've compared leverguns side-by-side and I'd say Uberti for absolute beauty, Puma for a more price-conscious Western gun, but great quality, and Marlin for a working gun (or CAS gun if you can afford their comp models, which you evidently can).