2004 Prius brake lights, are the LEDs changeable or not? And compatibility with later 2Gen lights.

I recently bought a used Prrius not more than a month ago. Everything is in great shape but the rear right brake light was extremely dim. I checked these here forums seeing that the only way to fix is to replace the whole fixture.
I took it to the Toyota dealership just to see what they could do. Apparently they replaced the broken LED(s) and it blew within minutes. They did some wiggling and jiggling of wires and tried again. It worked but told me it could blow anytime again. Now that lasted almost 3 weeks. What's my best route to fix?
Ordering the fixture from Toyota is $300+, I've tried two retailers online and they were sold out of the part.
If the early 2Gen models had the poorly engineered LED array, should I just buy a later model fixture (2008+)? I'm fine with having mix-matched lights as long as they work.