It is possible, however it would probably cost more to obtain the parts and have them installed than it would to order a Go Windsurfer 171.
Also there's possibility of finding a used Go Windsurfer 171.
What is it that you really want..... the retractable centerboard?
If so, what are your expectations of how the centerboard will change the way
your GO 171 sails?
Can you not simply stand a little off center (toward the upwind side) and use the rocker line
in your GO 171 to take you uipwind the same as the centerboard would?