acording to the USMC(some of my friends and this is a quote) if you check it in,when you ship out you can take it with you" so sidarms yes but thats about it
In RP military tech would be superior to civilian tech anyway. Why does it make sense in-RP to choose to use inferior tech? If you can come up with an answer for that, then you have your answer.
There was a question in the Special Character applications, the one that stopped me when I was drafting up a special application.
"Explain how the character's storyline cannot proceed without this request."
Even though you can use a civilian ship, I believe this question should be one you ask yourself before you buy any ship. Why does your character need this ship?
I find most of the time the answer is "I don't need this ship, I want this ship." And if that's the answer you give, then don't buy it. Just use one of the stock ships for your faction.