'Neo' means 'new, so the neocons are not the same as the conservatives. They are a group who have mostly changed their politics and become right wing. The traditional conservatives generally have a different political agenda- more concerned with small government and with a strong social agenda, while the neocons are more interested in foreign politics and projecting their interests abroad.
In Europe, when extrem right wing groups emerge, they are often called neonazis, because they take their ideology from those times, but they are not the same party, so they are a new version of an old idea. I think that with the neocons, the idea is to distinguish them from the conservatives, so there are two right-wing views and they are not the same. Neocons are probably not that interested in issues like whether the morning-after pill should be sold in Walmarts' pharmacies, which the religious right would feel strongly about. The ideology of figures like Wolfowitz and Richard Perle doesn't come from the traditional sources of the American right, like the religious conservatives, so I would say that, while modern politics is drowning in doublespeak, this is probably a distinction that is valid.