If you’re planning on this being a Skeletal Mesh that is rigged there is no need to have a lightmap UV or worry about setting one up.
However, if you’re going to have a static mesh version, you’ll want to setup a lightmap only if you plan to use it with any precomputed lighting (Static/Stationary Lights). The UV Channel 1 (in UE4) is the default location for all lightmaps, but this can be changed by setting the Lightmap Coordinate Index in the Static Mesh Editor to something else.
The biggest thing to get right with your lightmap is to make sure that the entirety of the meshes UVs is in a single 0,1 UV space with no overlapping faces. You can do this manually, or you can use the in-Editor tools in the Static Mesh Editor under the Build Settings to generate one. This can still be set to any index you want to use and does not have to be specifically set to 1.
Edit: Looks like Raildex beat me while I was typing. 