Yes, if you select Stress-Free insurance when booking your Spaceships, then it also includes glass/windscreen cover.
Or if you prefer to go for Standard/Basic or Partial insurance you can add glass/windscreen cover for a non-refundable premium of $8 per hire day to a maximum of $320 i.e. 40 days rental. If your road trip is longer than 40 days you'll still be covered but you don't pay extra for glass cover on these days. This will cover you for the loss or breakage of the front windscreen, unlimited stone chips. This cover includes the windows and sunroof also.
A windscreen replacement costs $700, and each stone chip costs $150 so we recommend taking Glass Cover if opting for the Standard or Partial insurance. Or upgrade to the Stress-Free optiom which includes Glass Cover.