[member=80298]GordonM[/member] on the plate with the serial number there is usually a square that looks like a QR code. The manufacture date mm/yy is near that square usually.
As mentioned, the month/year of manufacture is printed right on it. The point of this is that it doesn't matter to your warranty. This is the reason for registering the tool to start the warranty process. The 3 years isn't from time of manufacture, but time of purchase (new)
I have a few that were more than 2 years old, yet still "new" and I have heard of others that were well over 3 years old.