This is the regular non-enhanced issue:
https://atomicavenue.com/issue/254992/Batman-500
and this is the enhanced cover:
https://atomicavenue.com/issue/234041/Batman-500CS
Also, if the cover is already in the system, just having a signature should not make it a variant, COA or no COA. This is something I have said in the past and I think it really needs to be addressed again. Anyone can print a COA on their computer. If the cover is EXCLUSIVE to the signature then it would be a variant, but just a cover (Book) that has been signed, does not a variant make.