The part lines are very clean and look as if they have been considered a feature to display:
I kind of doubt that, but certainly a “detail” that warrants consideration … the flash might constitute a child-safety concern if left too sharp so “softening” the P/L would be a necessary step.
You might want to keep in mind that roto-molding is a relatively crude porcess; most tools are cast, or fabricated, aluminum (bolted/unbolted (for filling/part removal)) each cycle), and the process itself is border line Neanderthalic.
Not exactly high tech, but perfectly suited for the intended use.
(couldn’t believe this image popped up)
In this video they are molding vinyl (the resin is in a liquid state); pelletized material is the norm. The process itself is generally the same, regardless of size.