The FL-8988 should be the correct one for your 1960 manifold gasket. Maybe the one you got was mis-packaged.
Kevin, I'm betting they packaged the first gasket incorrectly. I just had an 8988 gasket show up today and it is the correct gasket with holes closer together. I'm contacting the seller of the other gasket to get a refund or send me the correct gasket. I don't mind having a spare.