Unless the HD cooling option was ordered - there were a good number of SS350 cars that had a clutch fan.
Check your radiator code before assuming...
HD cooling had no affect on the fan. "The V01 HD radiator option did not affect the fan usage."http://www.camaros.org/coolingsystems.shtml#fan
Out of 400,000 non-AC V8 cars that could have the optional clutch fan ordered, only 1% of them had the option. Even if most of these clutch fans were installed on non-L78 SS cars (not very likely), under 5% of those SS cars would have them. So yes, your SS350 or SS396 (325hp or 350hp), if without AC, likely came with the standard four-blade fixed fan.
The aluminum is to keep the rotating mass down.