Source may not have specular maps, but it has something that fakes it very well. The snow texture in Day of Defeat: Source has a specular effect.
I'm not sure how it's done, but some textures react to your flashlight as if they had a specular map. I think it has to do with the way they faked the blooming as you look into the sun. I want to say tone-mapping, but I'm not positive if that's being used.
Although I think you can't get that effect on anything animated, as no NPCs or other players are affected by the flashlight, which is annoying in multiplayer maps with dark places.
And with their HDR, they can get the effect of having certain areas on a texture brighten/bloom more than others. It looks awkward in places where the blooming area is abruptly cut off in shadowed areas, but it still pulls of the effect of a specular map fairly well because it changes it's brightness as you move.
Here you can see no specular effect on the hands or the gun. On the edges of the gun, there's some gray areas where the paint is worn away that are baked in the diffuse map but don't react to lighting conditions like a specular mapped gun would.
One positive of not having specular maps is that nothing I've seen on that engine suffers from the "it's made of plastic" look that's hard to avoid with real-time lighting + specular mapped engines.