Check out the photo below on where to locate your key number.
Your key number is typically 1-2 letters (your Key Prefix), followed by 4 to 6 numbers (your Key Number). Some New York Lock models will have the number stamped on the keys following the sequence 2 letters and 4 to 5 numbers or on a metal tag on the original key ring.
Some older keys will vary.
The key number is not located on the lock or the packaging.