... I'd visit your local Roofing Materials Supplier (found in the Yellow Pages under ROOFING - SUPPLIES) for info. And if you can, bring a sample w/you. Try a few Suppliers. GAF may make them. I know they still make Asbestos Cement Siding Shingles.
My best to ya and hope this helps.
Jay J -Moderator
PS: You can visit GAF's web site and e-mail them or poke around ...