In this MathEducator StackExchange article, "Notation of points with coordinates", it's posed the question about what is the best notation for geometrical points and their coordinates: $P(3, 4)$ or $P = (3, 4)$?
Peharps History of Mathematics could help with this discussion: what is the first known written register of such association point <-> coordinates? Did $P(3, 4)$ come first, for instance?
Descartes' "La Géométrie" has no such explicit association.
Somehow, this question is related to the posts "When do we see for the first time the use of the Cartesian coordinates?" and "Cartesian coordinate system in Newton's work". But, in the references given, I've found no explicit association either.