No, JFK-LAS was one of the new domestic D1 markets announced a couple years ago -- https://news.delta.com/delta-one-ser...mestic-markets
Generally, when flying on D1 equipment on these routes, you should expect it to see D1 marketing and service standards. I say generally as they have changed up the number of D1 offerings on these since the announcement and sometimes they will swap FC with D1 equipment on certain JFK-SEA flights, but still market the flight as FC. Also, BOS-SFO no longer has any D1 service.