GB, Back in the real early 50's drywall wasn't readily available, but they used what they called plaster board it was kinda the predecessor to modern drywall. It pretty much looked just like drywall, in 3/8'' x 16'' x 96'' configuration. they would push these tacks through the gypsum board and bend them over to attach the wire lathe to it. Then they would apply the base or brown coat and finish it with the white or plaster coat. Also they were very rarely used in residential applications. I find