Side glass could probably be shipped with a boatload of peanuts, but I would be leary on the back glass.
I have shipped quarter glass before, small enough so easy to find box that works.
Yes, side glass is relatively easy to pack securely with bubble wrap and peanuts in a box with some buffer space and the words "FRAGILE: GLASS" in big bold letters all over the box. And, if you buy minimal insurance, they usually take a little better care of it because they want to avoid claims (especially with packages that have additional insurance coverage). The back window is trickier but can be done the same way.