Stock intake manifold casting numbers

[Longhorn Man]

I have access to an intake that seems a bit odd to me, and I need to find out if it is in fact an oddball and/or desirable.
It is a stock G.M. casting, high rise daul plane unit, it is an older one, it has provisions for the front oil fill tube (283/327 style), it is blocked off though. Also, there are no provisions for the later style (long pump) alt. The boss in from\nt of the T-stat housing is not there.
My friend came across it and grabbed it becouse he saw it was a high rise, but he can't use it due to the lack of alt provisions.
Are there any numbers on it that can positivly ID it? (If so...where are they cast)
Are there many intakes that are actually worth something? I hear the term "Z-28 intake" tossed around quite a bit, however, it seems to be heard about as much as LT1 or Vette 327.