If you receive an AutoCAD DWG drawing containing all its layers set to "Color: White, LineType: Continuous, Thickness: ByLayer", and the objects in the layers are individually colored to some common color and linetype, you can use the PropByObject tool to set the properties of the layers according to the properties of the first object in the specific layer. You can then return the properties of those objects to "SetByLayer".
The PropByObject command is a part of the PropByLayer utility - see Download. Once loaded (APPLOAD), you can run it by typing the command name.
The command prompts you to select a list of layers:
Process layers [All/Except 0/noXrefs/White/Names]
i.e.: all, all except layer 0, all except xrefs, white/unconfigured layers only, or a list or mask of layer names to process.
The properties color (including truecolor), line type, and line thickness are transferred.