A:
If there are any markings at all, they can be interpreted by web search or consulting a bamboo expert. Otherwise, safest course is to start casting 30 feet of line, starting off with lower weights, four weight, working your way up until you find a line weight that seems correct for you. of course you'll need access to all these various line weights and that can be problematic. But it's a practical, safe solution as opposed to stress testing the rods.