Boy that was confusing lol, but I think we've got it now, 15562576 is what seems to be the correct part# for that hose.
I thought GM would have used the diesel hose or compressor since it was a diesel condenser but after re-reading now I realize that the hose you're replacing would have hooked up the same way regardless of if it were a gas or diesel condenser, it would only affect the line you're not replacing.
The 305 catalog says 88964866 is the oem compressor, when I search that on Napa it brings up the same 12 o clock type you bought, only all new, not re-manufactured, so you're good on that. Looks like the 80s gas engines used the stubbys, the diesels used the longer compressors.
15562576 hose applications
This is the cheapest I've seen it online, but I'd definitely call them first to make sure it's like the one you've got.
https://www.gmcarpartsonline.com/p/AC-Refrigerant-Discharge-Hose/48129855/15562576.html