I'd agree that they look like die lines/scratches. It is not entirely uncommon in the IHC series, especially in 1863. There are also some in 1875 (here and here) and the Scarface from 1892 is very popular. A new 1869 Scarface was just attributed, too. Hub-through wads of cotton, lint, or some sort of fiber have also been seen on the reverse that provide a similar effect.
Well, the mintage for this year and mint is over 4 million. Undoubtedly, many dies were prepared this year. This makes it more likely that a die error exists because they used and made many dies. It also makes it likely that a new die would have been ready and on-hand if the mint employee noticed the oddity, which is very likely. It is suspected that the reason these Scarface varieties are rare in the IHC series relative to other varieties is that the mint employee noticed the oddity and changed the die. You'd think that there would have been some quality control before they seat the die and start hammering coins. Why wait until the press is running to check for errors on the new coins? Maybe the employees were being pranksters to each other, who knows. Anyway, I don't know of any gold variety listings. My hunch is that they wouldn't carry much of a premium, unless they were something like a multi-denominational clash or an overdate. Perhaps others here know more...
