Wierd, I thought FIC always engraved the size in them as well, right next to where they engrave FIC. I personally don't know any other way besides getting them flow tested. Not sure if there's anywhere local that can do that.
I sent a email to FIC with the part number and got a reply back in a day. I just wanted to make sure when I bought mine that they were really what I paid for.
Have them flowed. There has to be a few places in the TC area that do it. If you know someone that goes to school in Kato they could do it in the Engineering Projects Lab.