There are two different OATHs you can do. One if your Religious and the other for none believers with different wording. On your AFCO4 it used to have a box to say if you were a nonbelievable and then I used to confirm my applicants on the Documentation check before Attestation. It was quite funny hearng some of the applicants trying to practice especially getting toungue tied over Heirs and Successors.
You dont get a days pay anymore, I did in 1987 when I joined up but all you get now is the Qath of Allegiance certificate, Train Warrant for the ATR and if you get a nice Recruiter like I was BFH(as per the programme Bullseye Bus Fare Home)