On the one hand, PCB layouts are considered copyrighted information, and copying them verbatim is a bad idea for legal reasons.
On the other hand, the PCB layout of an evaluation board is pretty much a reference design for how to Do It Right.
Are there any issues with copying the eval board as closely as possible? I would assume that it's meant to be copied, as their primary goal is for you to keep buying their chips and not have problems with them, but I've never seen this specified anywhere and the datasheets and eval board manuals still have the standard "All Rights Reserved", etc.
Reproduction of information in TI data books or data sheets is permissible only if reproduction is without alteration and is accompanied by all associated warranties, conditions, limitations, and notices. Reproduction of this information with alteration is an unfair and deceptive business practice. TI is not responsible or liable for such altered documentation.