Yep. It's as simple as that. Most of the time this is all it needs and if there are no more serious complaints then you don't need any more serious repairs.
One word of caution. The recess the seal goes into is a lot deeper than it needs to be. The seal can be driven in a lot deeper than it currently is. Make a note of how deep the seal is currently and when you drive the new seal in set it at about the same depth. Not rocket science but I drove mine all the way in before I realized it. Still works tho, you just can't see it. Lube the lip of the new seal with trannie oil when you put the shift lever back on.