The answer is in the FCOM
Here is the quote from Section 5 Approach and Missed Approach
Note: When performing a normal approach using flaps 15 for landing, if a go-around is required use flaps 15 for go-around. Authorized operators with appropriate performance data available, use flaps 1 for go-around if required for performance.
I would suggest that if it is to be a ‘Flap 1’ call on the Go-around, the QRH will say so (as for single engine)