I am not 100% sure but I would think not. I believe you would need to upgrade using the Upgrade assistant you can get on the 1st link
here and then update it to that KB. Cumulative updates just include all the updates that fix problems with 1803 but I think you still need the base version to use them.
Depending on your internet connection speed, and how long it would take to dl 4gb, you may want to just wait a few weeks until 1809 is released and just update directly to it