What would lead you to believe that it is a details coin? Please point out why you would come to that conclusion.
You've an interesting reverse, did you notice (...forgive my shakiness with the ballpoint pen in Paint)?
I can't speak for @ksparrow, but I went MS Details because to my eye, aside from the dipping, there appear to be scratches from a cleaning. I guess we'll find out...
Neither of those look like that to me, but they did come from the die. The lines down just left of the leg could conceivably be thick die polish lines, but I really doubt it, in this case. Take a look at some other reverses from this mint in those areas, I doubt you'll find these, not from any mint, for that matter, they're that unique. I think it's cool, actually.
I was undecided between AU55 and AU details, since it looks like it could possibly have had a light cleaning in the past. But it looks market-acceptable to me, so I gave it the benefit of the doubt and went with straight AU55. Nice coin.
Pretty sure the area in the shield is a die clash, as I mentioned back in Post #5. Here is another 1858 P Seated Half with the same clash in the shield that I found while I was trying to see if it was a well-known recognized die variety. EDIT: Here is another with something in the exact same spot, although it looks a bit different. Didn't see it mentioned on PCGS or NGC variety pages, nor is it in the CPG.
I see your Post #5 where you caught that, now. And this, another 1858 from the same Mint, is compelling. Thank you, I think you're right. What about that lower area I've circled, any thoughts on that? I very seriously doubt those are die polish lines. I think they're way too regular and prominent, as in "strong," for one, and two, there's no evidence of polishing elsewhere on that die. Yet, look at that area in these, regardless of Mint, and those lines are absent, not part of the design. Just look back at yours in CoinCommunity, that backdrop isn't there.
Yeah, I don't see those parallel lines on either of the CoinCommunity Halves either. They do remind me a lot of the same area on some Morgan Dollars I've seen...so my first thought was die polish lines/die scratches. They do appear pretty straight and parallel, though...my brain isn't quite in "Run" mode for the day yet, so I'm having trouble envisioning where a die clash would produce those shapes from (would have to be the shield, right?)
Here's a CoinTalk post hiding in the Google search results where @Mark Metzger does an overlay: https://www.cointalk.com/threads/seated-liberty-die-clash.318773/ That coin also does not have the lower left parallel lines.
That brings us back to some sort of localized scrape or tuckpointing to the die. But then, why nowhere else, just there, behind that one berry? The rest of the die is but flawless, it’s a real clean die. A little strange.
Ok, food for though. Not committing to grade yet, but look at the level of surface preservation compared to Photograde of a low grade MS coin. Interesting, isn’t it? This coin’s grade is definitely a curveball for certain.