Was using a VIN Decoder and all '77 VIN's I entered only specified Cutlass S. The 5th digit/letter shows engine size, but I only get Series=Cutlass S and Body=Coupe and nothing specifying it's a 442. Was that considered an option and not a vehicle, like they did in '72 ?

 

Yes, 4-4-2 was an option package in '72 and beyond and did not specify an engine, only trim and suspension.

The 4-4-2 was only a distinct series from '68 through '71.

 

So I guess the only way to ID a "real" 76 or 77 442 would be window sticker or broadcast sheet.

 

Pretty much, although other original owner documentation could possibly seal the deal. And of course, if it was originally built or sold in Canada there's always Vintage Vehicle Services.