The insignia on your shirt is pre-1939. To be correct, the collar should have twisted white and sky blue collar piping. If you wish to have a correct shirt, you should change the insignia to post 1939 pattern insignia when the collar piping was omitted. The insignia would include unpiped collar tabs and the 2nd pattern shoulder strap.
LIFE'S LOSERS NEVER LEARN FROM THE ERROR OF THEIR WAYS.
thanks for your advice