Filler's random models.

[Turbo Thunderbolt]

Blender when importing DAE files doesn't like it when you try to merge the separate parts together.
in fact, losing the uv mapping in general is why I hate DAE format models and hate working with them. Sure Rigging's intact but that's at the cost of losing uv mapping. I suggest saving it as an obj file to be able to merge them together and transfer the rigging if any from the 'dae' copy