I also checked the detailed notes I made on my own twist barreled DS grade guns. Neither has Nitro Special style checkering.
Curiously, one has the same 59xxx serial number range as your gun. My notes say it has a light H stamp under the right barrel near the serial number, and all numbers match. And the other gun has a serial number of 49xxx on the frame, barrels, etc. But it also has the same 49xxx serial number on the inside of the sideplates, and the left sideplate also has a second 59xxx serial number. It seems an odd coincidence that numbers in the 59xxx range are associated with your gun, and both of mine. I wish I had recorded details on the other twist barreled DS grades I've seen, especially the serial numbers. It kind of makes me wonder if there was a shortage of non-dolls-head frames to fill orders for DS grade guns during that period of time, so guns with H grade features were stamped DS to fill orders. Just a possible theory, with no evidence. Those long lost Lefever factory records make things difficult, and lead to a lot of confusion.
Based upon literally thousands of sales and auctions of Lefevers I've watched over the years, the percentage of DS grade guns with twist barrels and other H grade features is certainly very small. I was going to return the first one I bought, because it was advertised as having fluid steel barrels. This was before I had began to appreciate the craftsmanship and artistry of twist and Damascus barrels, and I wanted a shooter... and we all know that twist and Damascus guns are dangerous time-bombs that should never be shot! I spoke with Robert Elliot about it, and he suggested that I should keep it because they are a rare and interesting variation. I'm glad I took his advice.
