yes I would prefer that way, ARP measure instead of phase center measure.
watch out in the RINEX header of your log.
If UBX log is being post processed to recompute the absolute position (eg NRCAN service) ones has to force in the RINEX header the Rec #/type/vers & Ant #/Type
then NRCAN reads correctly the antenna model and returns L1/L2 phase center height in the PPP solution (the solution will therefore be the absolute position of ARP), like below (it’s an extract of NRCAN report)
I don’t know yet where those 2 phase center values have been determined.
I just know RS2 has been referenced in NOAA ANTCAL https://www.ngs.noaa.gov/ANTCAL/LoadFile?file=ngs14.atx
antoine