Review on GM Genuine Parts AC Accumulator 15-10421 by Robert Bigelow

I had no problem installing this on a 2000 Silverado 5.3 with no rear air conditioning but when I opened the factory sealed box which appears never to have been opened since the original packaging. , black exhaust cap and screw were loosened in the box. There was still no seal on the black cover and therefore the battery would not be sealed against the atmosphere even if installed as shown in the picture. I suspect it's not required in this application, but I'm not sure how that would be the case. There is a dryer.