Okay, now I see... Rich stated that even though the part number was apparently the same (3919060), it's a GM Service Replacement part (correct 68 grille styling, but no chrome). So it does appear that the 3919060 was changed to a replacement part at the end of the 1968 model year. That's why the 9/68 P&A shows 1967 and 1968 as both using the 3919060. Boy, they didn't waste any time in getting rid of that chrome did they!!!
And no, the P&A 26 doesn't show any kind of description. It shows Part Number, Group Number, Model where used (Chevrolet, Pontiac, Oldsmobile, etc...), Warehouse Code (where you could order it from) and the 3 layers of pricing:
"Suggested list" - what we as a walk-in customer could buy it at, and of course, the most expensive
"Suggested Trade" - what Resellers could buy it for, or, if you had a buddy in the parts department, what you could get it at if he liked you - middle of the road pricing
"Dealer Trade" - What dealers sold to each other for - the least expenive.
These are really cool books if you like to cry over how much (or little) things cost back then! For example, in the 1971 P&A 26, the price for the 3919060 is $10.75 (List) or $6.45 (reseller and dealer)!