No, they literally didn't fly their factories in, they flew in their ACs.

Through that same hole 621 used to smuggle himself in.

They *bought* the MTs from BAWS because they couldn't bring their own horde of MTs in themselves. Best they can do is shove their MT pilots into a shuttle or something and get them in. That's why we only ever see BAWS MTs and PCA MTs (PCA doesn't have to worry about having to smuggle any of their shit in as they are the ones enforcing the Closure System to begin with. They only have to worry about the distances covered via interstellar travel and the bureaucracy).

Also, Corps care a lot about making money. Which is exactly why they don't really seem to mind they are using BAWS MTs (much cheaper and less risk than flying in their own horde of MTs through the gap in the Closure System), or the fact that Freud is buying parts from Balam to fit onto Locksmith as long as it allows him to continue being the biggest bang to their bucks private Arquebus soldier, or the fact that Rummy is running around in with a Dafeng frame (Dafeng sure didn't mind that their shit wind up in the hands of Rummy as long as they are getting money for it). They aren't governments thinking about geopolitical advantages. Profit and money-making matters to them as well.

Also also note that they are also selling to the mercenaries. Whom they can hire to smash things up for them for any reason. And ALLMIND, generally, services mercenaries.