If I could afford a new blaster with steel grips I would buy one.
While steel grips were more than 50% of the survey, polymer still came in a rock solid at 37%.
But, I have deep, empty pockets...
USPSA Equipment survey indicates most use the STI grip vs. a steel grip. I think you already have something to work with. If it were me I would turn it into a very cool gun for a couple of grand. Less if the slide can be salvaged.