The guns with no name on the opening lever can be fine guns indeed, but, one has to appraise the individual gun. They were often built by outworkers, for a retailer, or a manufacturer, who would catalog and supply sliding breech guns. Most are 1894 patent R models, with brazed barrels, the earlier version that was replaced at the Darne factory by the 1909 R patent gun. The older patent was available for a few years at the Darne factory alongside the new version, but, sold to other builders as a proofed and in-the-white barreled action, out the back door, so to speak, for decades. I’ve not seen a “clone”, unmarked V model, and I doubt they exist, but, it is possible, I suppose.
It is very much easier to buy a Darne, then to sell one. Avoid project Darne guns.
Best,
Ted