I'm going to say no, you won't be able to take the school codes in. You will have to find them in the database. I can't remember exactly how it worked, but I do remember that you pick the school you're currently attending before you take the test, then choose where you want the scores sent afterwards. It was a little confusing just because I didn't know they were going to ask about my current school.
The majority of graduate applications I've seen say they want ALL of your transcripts - even community college classes. I ended up having to submit six transcripts - most of them are totally unrelated to my degree - because I didn't want to take the chance of leaving something out and having it bite me in the ass later.
For the curious six transcripts breaks down as follows:
1. B.A.
2. & 3. Classes from two different community colleges transferred to B.A.
4. Certificate
5. & 6. Miscellaneous job-related classes at two other community colleges over the past ten years
(7. Post Bacc - applying to grad program at the same university so I don't actually have to submit it)
My paper was a booklet-like thing of pink paper. Lol. I think they gave us regular yellow number 2 pencils. I had a little freak out moment the week before when I realized I wasn't going to be able to use a pen for doing calculations - I am weird about sensory stuff and the feel of a pen on paper is much nicer to me. I managed to get over it with no ill effects.
I also had my picture taken - it showed up on the screen when I was starting the test and again after the break. They offered a sticky note to write down my scores after I got out of the testing room but I didn't bother.