I'm almost wondering if the fixture was originally designed to mount a standard round glass sealed beam headlight, and someone mounted (illegal, non DOT approved) lights such as the CBIE lights. I did this with my '70 Mustang years ago, and eventually reinstalled the sealed beam bulbs. The CBIE units used a replacable halogen bulb similar to the ones used on many cars nowdays.
Anyhow, that would explain the lack of DOT markings on the lens.
Look for DOT markings on the amber reflector also.
EDIT: I just googled 2004 Pace Arrow Headlights and came up with the same link ennored posted above. Looks like it to me.