How do I interpret SNP nomenclature?
Quick answer is yeah, the G is the "reference allele" as you put it.  The greater than symbol is acting as an arrow, ie, G goes to C, that is, G is replaced with C.

Actually you get a pretty clear indication of that if you look down a line it two where it mentions the frequency:


  C=0.000419 (104/247982, GnomAD_exome)
  C=0.000494 (62/125568, TOPMED)
  C=0.000538 (62/115296, ExAC)


The C frequency is way too low to be the "normal" allele.  It's rather the substitution which results in a missense variant. You can see more specific stats by clicking on the frequency button.  In this case they basically just say that in all studied populations the G variant is by far the most common.