They mention that several other such ports like the audio and power are easily replaceable so that seems a fair assumption. The modules are also track-mounted and appear to lock into place somehow, so it seems unlikely that the internal connection will suffer the same kind of torture an external port would.

It would be extremely difficult to damage the internal USB-C ports on the mainboard itself. The USB-C Expansion Cards are what cables would be plugged into and cycled repeatedly, and our Expansion Card bays also have mechanical retention features that mean the insertion of the card itself is always aligned to avoid wear or damage.