In common lisp, how can I check the type of an object in a portable way

I want to define a method that will specialize on an object of array type with unsigned byte 8 elements. In sbcl, when you (make-array x :element-type '(unsigned-byte 8)) the object class is implemented by SB-KERNEL::SIMPLE-ARRAY-UNSIGNED-BYTE-8. Is there an implementation independent way of specializing on unsigned-byte array types?