  Auxiliary system approach and various nearest neighbor methods are widely
used to detect generalized synchronization in non-identical coupled systems.
These methods generally give contradictory results. Therefore one method alone
is not sufficient to predict correct result. We show in this report that it is
necessary to apply multiple methods together to come to a conclusion. These
methods show a signature of generalized synchronization in diffusively coupled
non-identical chaotic parametric excited pendula. But we finally find it to be
the almost synchronization. It is achieved when the second Lyapunov exponent
and both the system's transverse Lyapunov exponents are almost equal. The
transition from asynchronous state to almost synchronization is through
frequency entrainment as coupling constant is increased. Non-identity of the
pendula are realized by mismatch in amplitude of parametric forcing. The
frequency entrainment regime does not depend on amplitude mismatch whereas
onset of almost synchronization increases with increase in mismatch. The
systems
