If you work up at Crystal, the roads can be terrible in the winter commuting from town. Small rock/sand and gravel do pit the windshields. It's been a real problem since the introduction of the TJ; IMHO, I think it's due to the rake of the windshield as opposed to the CJ/YJ.
As an ol' Buckley Boy, I used to take my kids up to Crystal at 3pm on a Sunday and come back to Enumclaw doin' the speed limit till I hit the White River Mill and then slowed down.
The kids called it "pissin' off the tourists." Geeze it was fun...
However, you can argue all you want about the reasons it's not DOT approved, but the fact is that it's not. The problem come if there is ever an accident that involves the windscreen shattering, splintering, or the like. There is no laminate sandwich to keep the windshield intact during an accident. What happens if your (or a passengers head) attempts to go through it. It can happen, and it won't be a pretty sight. Then let's talk about what happens if it does stay intact. If the windshield pops out (CJ) or the frame deforms and the windshield pops off the urethane seal it can fly back and destroy you and the passengers.
There's no protection for you and your insurance company (once they find out) will back away as the opposing lawyers descend on you like a pack of wolves. If they find out before you have an accident you'll be dropped like a hot potato.
Do yourself a favor and keep the glass and keep up your comprehensive insurance. Mutual Of Enumclaw is who I use...
Oh, since you have a 84 Toyota and haven't see the Top Gear Video, it's worth the look: