How was this molded?

[Swisscheese]

This is a nose cone of a toy glider. I'm trying to figure out how it was made. I suspect it is HDPE but mainly wondering about the process. It is hollow, ~5" long, with a wall thickness of ~.014". Notice the D shape at the tip and the small round hole - perhaps they are clues. Is it likely injection molded or vacuum formed or something else? I can barely see a seam all the way around and at one spot the seam is not so uniform hinting at sealing by manually pressing a heating element to seal but the rest of the seam seems too clean for that. I estimate that the manufacturer makes ~1,000 per year.