Not sure I have found it anywhere but are dagger slides 416 stainless?

If so are there any durability concerns with them?

In the SHOT Show 2020 timeframe, PSA had said the Dagger^TM slide was 416 stainless steel.  However, like you, I can't find it documented anywhere at the moment.  I asked this exact question on the PSA Dagger Forum, however, I never received an answer.

I'm not aware of any durability concerns with the stainless steel.  There have been several reports of the Dagger^TM slide coating chipping with normal use.  I'm aware of one case in which PSA has offered to repair or replace a chipped Dagger^TM slide.  NIC Industries, Inc., the parent company of Cerakote, is currently working with PSA to improve their application process,

http://palmettodagger.com/SlideCoatingChips

Personally, I don't believe the issue is with the application process, nor specific to the Cerakote Dagger^TM slides.

For more information regarding the Dagger^TM including the Dagger^TM Barrel Manufacturing Defect, refer to,

http://palmettodagger.com

the item description for the dagger on their website states Slide Material: stainless steel. no number associated.