Personally, I'd probably go back to sea school and re-do the course.
I understand it's an expense of time and money that you may not want to incur.
If you just take the CG test, you'd still have to put in the time for independent study, just not the money. And you never know what questions you'll get.
Sea School will gear you up for their tests.
Do you have your Twic card yet? You will also need to start that process if you don't. The coast guard won't issue a document without it.
You'll need a drug test for the CG and new physicals and eye exams.