If nobody has on the Forum go to Facebook and find Scotty Strickland in Buford, N.C. I think is where he lives. He has a mustang junk yard. The windshield piece is tough to find for any body style they get very brittle. You might try running ad in Craiglist or FB Marketplace in the north east. Plastic lives longer there.
make sure you get it for the right car, fastback, coupe, etc. The A pillar pieces look the same for a fastback and a coupe but they are different. Fastback will have 63 in the part number, coupe, 65. They are more fragile then eggs, I have a spare set squirreled away in a box engulfed in bubble wrap.
I have gotten a few things from Scotty and for me, not the best parts for sure but used parts are used parts I guess if you need them.
Looks like I only drivers side for a Fastback and a Coupe. Fastback has a little piece missing at the top, but that fits under the metal molding over the door. That is all I have at this time. Do have another Mach 1 coming in late May.