What surprises me is that any doctor would even consider putting you under anesthesia after having had GBS.
My son nates doctors all have told him that you run the risk of having a total relapse from the anesthesia.
His foot deformity would normally be corrected by surgery and his Ortho said he would not even consider it.
I would really do some checking on that aspect of it. Why run the risk when you could still get back good use of your hands? Your hands could get better with time. Most do.

Not to scare your and you might already know this but if you don’t, be sure to meet with your anesthesiologist and strongly let them know you have had GBS.
It can make the difference between coming out with no problems and having a relapse from anesthesia.
My son has been told by Nurses that it can happen.