I don't know anything about R51's on Remington Product display trailers, but I can otherwise offer a little hope & reason for delay from Remington reps.

This is about the RM380, but at around minute 4:30-5:00 or so, a little insight into R51 production...
https://www.youtube.com/watch?v=PloJMaooY4c

Also, I called Remington today inquiring about the R51.  Rep said R51 was being made, but not yet ready for release to public.

I've been searching for the most shootable, most accurate, most concealable 9mm available.  If they make the R51 reliable, I think my quest may be over.

My R1 was made in their new Huntsville, AL facility.  RM380's are being made in Huntsville, so...
.

I was an owner of the rare R51.  Accuracy was good. Reduced recoil meant +P ammo didn't tend to make the gun feel like it was trying to jump out of my hand.  Reliability, was an issue. I exchanged for their R1 1911, which is a nice, tight, accurate pistol.

A bit of updated info on the R51 from a couple of Remington reps in my next post in another thread.