3-fold ragtop question

I am in the process of acquiring 3 fold ragtop pieces. Did all years of

3-fold ragtop rails have the inlaid material on top? What is the inlaid material? Do the short rails have the inlaid material or are they exactly like the short rails on the 2 fold ragtop? I have seen plastic and aluminum short rails. What is the correct material for the short rails on a 3 fold ragtop? Any pictures would be appreciated. Thanks, Dave