Gps numbering order

Hello if you have multiple GPS units is there always specific order to the GPS numbers in the logs? Is GPS0 the first logged gps unit? Or will it always correspond to GPS0 in config? What if GPS0 is not plugged in right away on boot? Also what if one of the GPS units is HIL GPS? From what I’ve seen gps numbering doesn’t look to always be one to one. Which makes setting GPS primary difficult.