Hi harryg,
Here some facts as you asked for:
1) the Colombian Carlos IV 1 Real coins of that period (1792-1804) show the mintmark of Nuevo Reino with a period in between (N . R), as the numista example you gave in this thread shows very clearly.
This period is not visible in Coincoll22's coin.
2) since unfortunately I don't have the 1793 piece in good shape, here a 1791 1 REAL IJ from Peru with the mintmark LIMAE in monogram .

Please compare the assayer's initials in coincoll22's coin with the initials in this one; the "I" and the “J” a clearly different in the peruvian coin; in the colombian case they are not, because the initials are JJ.
And please compare de LIMAE monogram in conincoll22's coin with this one.
3.- Here a scheme of the most important Latin-American mintmarks in Spanish times, including the Lima monogram based on the latin name LIMAE. This monogram is mostly recognisable only as a ME in worn coins.

Kind regards
christianvl