This only matters if you pass in a function handle - if you pass in a matrix, EIGS detects if it's hermitian (real or complex) directly using the ishermitian function.
And in the complex case, issym is interpreted as asking if the matrix is Hermitian.
In the new interface using Name Value arguments, the equivalent of issym would be
eigs(Afun, n, k, IsFunctionSymmetric=true)
