I've searched but can't find a clear answer. I've read that 04 through 09 have alloy wheels covered with plastic wheel covers for aerodynamics. I read some owners remove the covers because the alloys look better. Is this true or was a separate oem alloy offered for gen 2? See pics below.
The OEM 16" rims on my 2009 Gen II, like many other things, look much better nekkid so the wheel covers were the first thing to be removed. Here they are in all their nekkid glory! https://priuschat.com/media/chuggy_fall3.15372
The pics you attached are for the 15" alloys. Those had plastic "rings" instead of full covers. The pic on the left is the alloy without the ring. The pic on the right is the same alloy with the plastic rings.
The alloy is what is on my 07. The cover is what is on my daughter's 09. If i remove her cap, what is underneath? I would pull the wheel, i don't have access currently.
Toyota uses alloy rims and wheel covers. Marching to a different drummer I guess. They tend to "ugly up" the rims too, imho. And charge exorbitantly for the center caps (traditionally called hub caps).
If you remove the ring, it will look like the left photo. They're the same wheel. The plastic cover is the ring (that's why I'm using the word "ring" and not "cover")
Very loose debate as to aero advantage with the rings. The rings can avoid wheel damage if the driver is a curb rider when parking as they will get rashed up before your wheel. But they trap dirt, road salt/sand for those in the snow belt which leads to premature wheel finish failure. I threw my rings away as soon as we got our Pri years ago and we still knock down around 50 mpgs with mixed, spirited driving conditions and we have about 127K on the clock.