You can buy new windshield flat head conical torx bolts meant for Jeeps on eBay.
I would much prefer torx to Allen head bolts. I replaced my 4 roll bar to windshield bolts with Allen heads and after a few times of lowering the windshield I had to give that up and go back to torx. Was just way too much pain in the ass factor and torx don’t strip as easily as a small Allen drive does.