[SS Tim]

Guessing this is what you rang me about... :-)

If you have been reading, then this should be fairly clear in concept. It just doesn't match what you are seeing.

A 70-72 truck, paint coded 557, a Special Two-Tone selection will always be painted GM code 506 Dark Olive Poly (Ditzer 2207) as the primary color inside, out and under.

The roof and upper cab are painted GM code 504 Medium Olive Poly (Ditler 2097) in the conventional two-tone pattern. In no event will the secondary color be found on the interior (it stops at the weatherstrip) nor below the cab divider trim (D99) below the rear window.

The white paint between the upper and lower bodyside moldings plus roof, seen on a great many trucks (very often added), is called Deluxe Two-Tone and is always a 4XX paint code from the factory. It is not correct in any way with a 557 code. Nor would any contrasting color between the moldings unless added by the dealer and documented.

However the SPID (or cab) is likely not the original for your truck if the cab is, as you observe, 504 Medium Olive from the factory. The VIN number itself appears to have been intentionally obliterated since it probably didn't match the VIN tag on the driver's door pillar (attached with rosette head rivets).

Even more curious is the fact the SPID is for a Cheyenne Super which is not too common for 71 since it was a very late introduction.

IMHO someone added the SPID (lwb, 1/2 ton fleeside) from a 71 to your truck or replaced the cab (changing the VIN) at some point. The SPID side of the glovebox door appears to be the original 506 Dark Olive Poly. Is the face still the same color or was it repainted Medium Olive? To me it sounds more like a cab swap than the classic "upgrade" of a lower trim truck using a Super SPID and possibly its trim.

Without more pictures its very hard to tell what you have much less what migh be original to your truck. At this point I would be looking very hard at the VIN plate, rivetts, frame VIN (partial). Then with this information see if any of the SPID VIN is there and matches on a digit by digit bases.

To answer your original question the firewall should be GM 506 Dark Olive Poly on a 557 coded truck.