The model doesn’t seem to have any seams, and yet all the diffferent parts are in the correct place and such. How was this achieved?
Seems in blender are nice to make the unwrapping, but AFAIK not used for anything else (?) and can be deleted afterwards. Think of it as splitting the geometry for easier UVunwrapping and mergeing again afterwards. Anyway you can unwrap different regions as you like…
I’m sorry, could you elaborate what you mean by this?
The “secret” here is that the texture is mostly flat color, so the modeler didnt have to worry about overlapping UVs and seam placement. Wouldnt work for anything more realistic.
I think @OkiDoki means: if this model was created in Blender, then sometime after it was UV-unwrapped, they deleted the seams (edit mode → edge → clear seams). You only need the seams at the moment of unwrapping, not afterwards.
If this wasn’t made in Blender, it might have lost the seams in a format conversion.
Sorry for answer so late. Your ask for the seams and blender can mark edges as seams for further easier UV unwarpping. But they aren’t needed anymore afterwards AFAIK.
Of course whoever unwrappered the model put them into the right places 
and as @DeckardX08 and @smws said: easy texture/ maybe not made in blender…