If you want the TSO stickers, tell them when you order the set-up. If you're only ordering the Uflymic and are supplying your own headset (QC-15), you'll need to send the headset to them. They're doing the certification to say that it all meets TSO requirments, so they require all components present. They can sell everything to you, or you can buy the Bose separately. If you buy it separately, it needs to go to them, and they'll certify that the whole kit meets the TSO standard, and put TSO labels on it.

I sent mine in, because I'd bought the headset elsewhere. It was a quick and painless affair.

To meet the requirements of the TSO, the ear buds must be worn. If they're not, it's not technically in compliance. I never used mine. I kept them in my bag, but mainly as a just-in-case I was halfway around the world and the earphones failed...they were just a backup to me, and I suppose I could have used them if anyone wanted to whine about it. Nobody ever asked. I did checkrides with the FAA on board and line checks, and nobody ever said a word about my headphones.

The QC-15 and uflymic are a great combination. They drastically improve communication, even in a quiet cockpit. That they fold up flat and take up little space in the flight bag was a big selling point, as was their usefulness when commercialling or deadheading somewhere. Put them on, and passengers nearby leave you alone. Listen to music in comfort, or just partially blot out the screaming infant six rows ahead.