originally equipped with catalytic convertor?

[aggie91]

I have a 1987 Chevrolet R20 3/4t, 2wd, regular cab longbed. It does not have cats now, but it looks like it might not have had them originally either. It has the 454 engine and I have been told it might not have had them from the factory do to its combination of 3/4T and the 454...

I don't know and the question has arrisen based on a state visual inspection of the exhaust system. The state requires a visual inspection for cats and muflers for vehicles 1984 and newer. The exception is some trucks where built without the cats from the factory, and if I can provide that info, then mine is exempt from that. No where on the truck can I find a label or sticker that indicates it should have them....

Can anyone shed some light on this? I know I should be able to look at the SPID or the vin number to get this info, but what info or code am I looking for??