I just removed the original top from my early 31 Tudor.I couldn't figure out what the strips were,they were paper backed.A trimmer friend thought it was cork,but I didn't think so.My reaoning was that paper backed cork was a pretty elaborate item to be using when there was tons of scrap material being dropped on the floor every day.It actually looks like asphalt impregnated cork on mine.I used strips of long grain top material that was scrap from another job.With the heavy grain it averages a little more than 1/16 thick.