I'm betting the photo is a one-off they did as a mock-up without having the requisite items; given the 'to order' nature of the product, it may have even been created and advertised before the game was 100% completed in terms of marketing and assembly. If it was a Christian-themed mail-order type deal, the carts were likely to be assembled on a per-order basis (though didn't Steve Stack state that he had created inventory for this and had it in a storage unit?), so this would imply that the ad mock-up wouldn't have a copy. The game appears to be Combat, so they simply used what they could find and cut/pasted in a screenshot of the game they were advertising prior to ad copy prints. The child coloring a picture of a lamb would add to this one-off quite well, since that would have Biblical connotations as well. So they grabbed an Atari system, three kids, and a substitute religious coloring book, made the one-off mockup, made sure the text for the cart wasn't 100% visible, then cut/paste the screenshot in.
Makes sense to me!
EDIT: Actually if you look at the television screen in the ad, the horizontal lines are off-kilter from the set itself. This wouldn't happen in an actual game being played, obviously, so that adds credence to the cut/paste nature of the ad setup. This adds up with everything else we know nicely, because the company obviously isn't some billion-dollar-volume retailer like Atari that would have huge ad print resources to create something perfect.
EDIT 2: After a second look I'm assured that's Combat in a Vader console. Look at the black near the text -- that's a much darker matte black than the gloss black of earlier text label carts. This means the label is one of the 'electrical tape material' style labels that Atari used later on. That label type was only used on ONE game -- Combat!
Wasn't that "electrical tape" style label for Combat used as the pack-in for the Vader console, or was Pac-Man the pack-in by then? If Combat of that type was the pack-in with the Vader, there you go -- they slapped everything together from a console someone either bought then or there or had lying around!