Having never played a Ranger to Epic Levels my knowledge was lacking.
I'm guessing the general rule applies here that whenever a character qualifies for an epic bonus feat with a class that also has bonus feats pre-epic (fighter, rogue, ranger etc.), bonus feats may be taken instead of epic bonus feats at any time as well.
As an example, you can pick Knockdown, which is a Fighter bonus feat, but not a Fighter epic bonus feat, as an epic bonus feat at epic levels. The situation seems to be the same with Rangers - Favored Enemy, which is in fact a bonus feat, not an epic bonus feat, can be taken at epic levels instead of feats from the epic bonus feat list.
In that sense, yes, you can pick a Favored Enemy at 23, 26, 29 etc. However, LORE seems to be correct, as Favored Enemy is classified as a bonus feat in NWN and not an epic bonus feat. I guess NWN classifies feats as epic bonus feats if they require epic character levels.