Just in case someone else can not get certified copy of passport.
I got married in Phimai amphur, Korat province.
Staff there was very kind and helpful.
All they needed from me was Certificate that I`m single with all the stamps from embassy and MFA and a copy of my passport translated to Thai without stamps.
No appointment needed, it took about one hour for all the process including my wife changing her last name and getting new Thai ID card.
We had 2 witnesses, but in case some one cant find them, staff will sign it for you.