If by GPS you mean a map in the glove compartment box, then yes. But you will probably have to buy the map yourself.
Lol, joking of course, I've never seen a car with GPS, let alone a rental. Sorry.
GPS is alive and well in the Dominican Republic.
I use a Garmin Nuvi with a Dominican Republic map, which I downloaded and installed myself.
My neighbor drives a Taxi and he also has a Garmin Nuvi with the Dominican map.
Mine also has a battery backup and can be used without a car for about 4 hours.
Have used it by hand in Sosua and Santo Domingo.
Chances of one in a rental car is probably going to be hard to find.
For one thing, it would probably be stolen.
D in Santiago