Questions about CF-19 MK6

Hi,

I recently purchased a CF-19 MK6 and have a few questions about it's upgradability, as well as specific parts compatibility.

I'm located in the US, and the model I ordered is a US market model, so all the localization questions should be answered with that in mind.

I've read that the half extended antenna covers for the MK6 cannot be replaced with flush ones, is this true? I noticed that there are quite a few pictures of MK6s for sale, as well as promotional shots that show them with...

Questions about CF-19 MK6