There's no way to tell without taking it apart. Chances are if it is still the factory stock unit it has a crush sleeve..but that is not absolute. I've seen factory ones with a solid spacer before. It can be done with a crush sleeve still...you just have to be real careful or you'll be replacing the crush sleeve along with the seal.
![Tantrum :tantrum:](https://board.marlincrawler.com/Smileys/marlin/tantrum.gif)