In general the bark of hickory is smooth and blotchy but young trees of almost any kind are also like that. There is a shaggy bark hickory, and it is just like its name shaggy looking bark. Some make a sweet syrup from the shaggy bark.
Hickory is a very dense wood and even when seasoned is usually heavier than oak. The upside is oak is also good for smoking so not a terrible thing if thats what you use.
There are many pics you can google, try googling your states Conservation Department for more info.
One last thing don't forget to season your new cooker before using it.
When the going gets tough, I take more fiber.