The short answer is yes. A "useable" GG can be made with a sandblaster and I have done this myself. When I bought my 8x10 Agfa, the GG was horribly poor. It wasn't just dull and scratched, but the edges were chipped and it was almost dangerous to my fingers. While waiting for Dave Parker of Satin Snow to make and ship one, I sandblasted a chunk of window glass with 24 grit silica sand and it made a suitable short term substitute.
Satin Snow's GG when it arrived was far and away a better piece and I wish Dave was not only still posting here, but was also shipping to Canada (I don't think he is).
The only change that i would make if I had to blast another one would be to blast with a much finer media, possibly as fine as 100 grit if available.
cheers