I believe that only applys to the model 03, not the 03A3, but I could be wrong.I think there is a serial number range (early) that are not safe to shoot BUT, I don't own one so don't take my comment as gospel. Just something I remember reading.
The heat treating method was immediately changed to a double heat treatment, and pyrometers were used to determine the temperature of the heated receivers. The change in heat treating was instituted between serial number 750,00 and 800,000 at Springfield and by serial number 285,506 at Rock Island Arsenal. Rifles manufactured after these serial numbers are referred to as "high numbered" receivers and are commonly stated to be safe to shoot.