I too find it questionable that it's a Rylo although it certainly looks possible.
As said before, they have access to the LFL archives. That means they have the original ROTJ "Hero", the 2-3 versions made for the ST (I'm guessing the TLJ/TROS are the same saber since it was barely seen in TROS), the MR versions, and the Disney legacy sabers all within arm's reach so-to-speak.
I'm not saying they WOULDN'T use fan-made stuff, but this isn't the same as TLJ/TROS where they needed a Graflex replica to beat up. Regardless of what they ultimately used, it's not like we will ever know why they chose whichever version they used. The only sure thing I suppose as far as their intent was that they deliberately wanted something more like the ROTJ than what was seen in the ST.
I would have personally loved for them to use the V2 but I guess Luke has had a few years at this point to clean his saber up whereas in ROTJ he had just recently built it from spare parts found in Obi-Wan's hut.