Aug 30, 2015 - 05:45 PM
Short answer - absolutely yes! Check the builtin asset: 40ft Boxcar 1937 AAR Mesh Library for an example.
As a content creator, the question you'd want to ask yourself is "Is this mesh/texture used by multiple assets, or likely to be usable by multiple assets by the time I'm finished". If yes, then creating a library so that content can be shared will help performance.