In theory, it should still be “water resistant “ after you replace the battery (this if you also replace the original adhesive).
But in reality, it probably isn’t going to be 100% “water resistant“, it’s extremely hard to get a perfect seal that stops all moisture. I wouldn’t even trust that it really is that when it comes from the factory.
Depending on how you manage to place the new adhesive, it should work to stop most moisture to come into the device.
But I would recommend using a waterproof case if you are planning on taking a swim whit the device on you or something like that when you have the device underwater for a longer period of time (this even without opening the device up).
Hope this answered your question. :D