Looking at mine, nothing in the serial number is anything close to what year it is. I think the serial number just keeps running consecutive once they begin that number series.
NH 1630 W-7308 FEL/ Kubota L4630GSTC W-LA853 FEL WQ/A-CC 2544
With the serial number a dealer will be able to tell you what year your tractor was produced. Once they start with a serial number it just goes to the end of production. There is no way to tell what year it is by just knowing the serial number.