I recently acquired a 1974 Raleigh International. The bike is like a time capsule in that it hardly seems like it has been used. One odd thing though, odd to me anyway. I noticed that on the rear dropout, on the top side of the drive side axle slot, the surface is knurled. I've never seen this before and wondered if anyone on the list can enlighten me on this. Was it a widely used practice? Is it meant to keep the wheel from slipping in the drop out? Is this a miscasting, or bad machining? (I don't think the latter applies, as the drop out looks just fine, and the knurling intentional). Can anyone comment on this?