Re-light proofing the curtain is relatively easy, just go and buy some acrylic black paint, prefereably matt, lamp black. Then work this into the shutter curtain, you have to get this paint into the cloth itself , do this on both side then wipe of the excess, this is important to keep the flexibility.
This works with even quite bad shutter fabric where I've had to strip of flaky light proofing, it's quick and very inexpensive.
I've done this to a pre-Anniversary shuuter cloth in situ by doing a section at a time with just the back removed.
These days I find it's simpler to just replace the curtains when I restore shutters. If you can give me the measurements I'd make you a new curtain, but I can't do that until I make my new batch of shutter cloth (or my wife brings my existing cloth back from Turkey). I will look up my Graflex pattern as well and you can see if it'll fit.
Ian