Does tapping "Disable and Download Messages" delete any of the messages on my phone?

I would like to stop my iMessages from being synched to my iCloud account. When doing this, I have the option of tapping "Disable and Download Messages". Does this only download messages from iCloud? I don't want it to delete any of my iPhone iMessages.

For example, say I have messages A and B on iCloud. And I have messages A, B, C, D, and E on my iPhone. (I believe iCloud ran out of space before all my messages could be transferred to iCloud.) Then I disable iMessage synching to iCloud on my iPhone (toggling Sync this Phone to the off position). Then I am asked to "Disable and Download Messages." If I tap "Disable and Download Messages", it will only download messages. It won't delete any of my messages on my iPhone, right? So, at the end will my iPhone will have A, B, C, D, E.

The reason I ask, is that I don't want my phone to be synched with my iCloud messages, which would mean that messages on my phone would be deleted.