I have not seen any thing on polymorpism in Perl.
You can't have inheritance without at least one
level of polymorphism: dispatch on the target object!
So, the answer to this is a simple yes.
However, you can have multiple dispatch using Class::Multimethods, so the answer is even more far ranging than first seems.
Is Perl a true or psuedo OO Language?
Well, to answer that, you'll need to define "true" and "psuedo (sic)". Perl's OO support is decent, and Perl 6 will only be getting better.
Perl is as much of an OO language as C++ or Java or Python. Ruby and Smalltalk and Eiffel are a bit further up the scale, since they're actually "pure" OO. Perl, C++, Java, and Python are "hybrid" OO, with primitive pseudo-objects and pseudo-classes that cannot be extended or subclassed or introspected.
-- Randal L. Schwartz, Perl hacker