Yep, a portfolio would be a very good idea.
C2 is supposed to be non programming, but it isn't really beyond the trivial, it's just a different way of doing it. You still have to plan, document, track events and so on. If I was looking to pay someone real money I'd want to see what their planning, design, code and documentation was like. Do they bang stuff together or do they think ahead, reusability and modification sort of stuff.
I've worked on bought code before (offshore stuff) which was absolute rubbish. Infamously, once, 600 lines of C which looked like FORTRAN (a,b,c,d variables) which was two functions with no comments at all. I rewrote it in the end.