Looks like there is a great deal of flexibility on what constitutes Firearms Training requirements. Here is what is posted on the El Paso County Sherrif's office page:

Firearms Training Requirements
The applicant must submit with the application the original certificate or a photocopy of the certificate with the instructors original signature, affidavit, or other document from the instructor, school, club, business, organization, or group that conducted or taught the course or class, attesting to the successful completion of the training. All documentation must have been obtained within the 10 years preceding submittal of the application.

The applicant demonstrates competence with a handgun by submitting any of the following:

Evidence of experience with a firearm through participation in organized shooting competitions or current military service;
Evidence that, at the time the application is submitted, the applicant is a certified instructor;
Proof of honorable discharge from a branch of the United States Armed Forces within the three years preceding submittal of the application;
Proof of honorable discharge from a branch of the United States Armed Forces that reflects pistol qualifications obtained within the ten years preceding submittal of the application;
A certificate showing retirement from a Colorado law enforcement agency that reflects pistol qualifications obtained within the ten years preceding submittal of the application;
A training certificate from a handgun training class obtained within the ten years preceding submittal of the application. The applicant shall submit the original training certificate or a photocopy thereof that includes the original signature of the class instructor. To the extent permitted by section 18-12-202 (5), in obtaining a training certificate from a handgun training class, the applicant shall have discretion in selecting which handgun training class to complete.

Found the last point interesting.

Date of my military retirement is outside the 10 year mark, so guess it is time to sign up for a class. Doing a CCW class might not be a bad option since I haven't taken one, plus my son has expressed interest in carrying as well. Magnum's Tactical Move and Shoot class would have more of the "fun" factor.