HI I will be able to answer the questions re Model size , v soon as it will turn up on my door early nxt week.
I think it is the 1.20 version.
The guy selling it stated that it was for a 1.20 YS, he has one for sale a YS FX 1.20 with tuned pipe and header.... was interested but our boys at the field like ballistic pattern with high revving 2 strokes and I was hoping to join in the high speed action.
The YS has crossed my mind a few times though.