6-5 referee assistant games

Egg man

I've had a few 4th Official appointments in cup finals recently does anyone know if I can mark them down as a Assistant Referees towards my promotion from 6-5?
The Referee Store
I'd be very surprised if so... You're not acting as an assistant referee nor are many of the skills aligned.
I can answer this with absolute certainty, definitely not, the purpose of needing the games as assistant is to get you experience in that role. You just aren't going to get that experience as 4th official.