Heat Pump age help

Darn darn darn. My Prestons CD got scratched and won’t open. Need some help with this Coleman unit. Thanks in advance.

Model: DRHS0421CD
Serial: 000385622

Coleman: Serial numbers prior to April 1992=1st two numbers are month, then year, then series.
After April 1992, 1st two numbers are year, then month, then series.

So March 2000.