The earliest European fishing rods were made of different types of wood, spliced to gether, and were often very long, 18ft. being common. Tips were often made of greenheart, whale baleen, or on the later rods, bamboo cane. It was only with the late 1800s that split bamboo was being used to make the whole rods in any great numbers. The shorter a Bamboo rod is the more collectible it seems to be. A seven foot rod by a famous maker will usually be worth 4-5 times what a 12 foot salmon rod by the same maker, despite the salmon rod being harder to find.
Condition is a tougher subject.
A split bamboo rod, restored to original by a professional restorer seems to retain much of its value. The same rod poorly restored, or used long and hard has little value. Beware of made up rods, that is poor quality cane rods, that an unscrupulous restorer has attached a handle from and expensive rod, and trys to pass the whole conglomeration off as an expensive rod. Of course having a rods original cloth bag, and rod tube that it came with will add to its value. Make sure any split bamboo rod is original lenth.