japanese/canadian bed?

a guy asked me about a combo that has a "rail" all the way around it, he mentioned maybe a japanese or canadian one.. but im not familiar with those, figured id ask here if anyone knew what theyre referred to as or the year

84-88 had the jap and american beds. The difference is they have a dip rail in the bed. Like Rodneys truck. Grant offers a rear skin for them, but you have to use your stock ailgate rail off the top.

Yeah I got the Jap bed......its got the big ole lip that floats around the whole bed.The other bed was smooth at the top and had a wider fender,it kinda bowed out.

We have both options here in oz. why would you want a rail around the top? They either get the chop or welded up.