How about calling them and see if they will add it for a small fee? You'd pay a local the fee.
SALES AND CUSTOMER SERVICE
Our telephones and email are answered 8:00AM-5:00PM Monday-Friday, MOUNTAIN STANDARD TIME excluding major holidays. Galco’s corporate office and factory are not open to the general public for retail sales, repairs or tours.
Galco International
2019 West Quail Avenue
Phoenix, Arizona 85027
1 (800) 874-2526