To anyone still interested:
Stefan found out that you can find if the player has an instance of the string with the space (Gold Platemail ) by using getstringkeys("clientr.item-Gold Platemail").
After that, I figured out you can do something like this:
PHP Code:
temp.gpmstring = "clientr.item-Gold Platemail ";
clientr.("item-Gold Platemail") = {makevar(temp.gpmstring)[0],"armor/chest/goldplatemail"};