Generally speaking (in other words, not sure about sinensis but for the other camellias, a month-ish would be "normal" if they were harvested when the order came "in" to Ebay and planted with a light layer of soil. If they were kept refrigerated in plastic bags then later, even as late as next Spring?

Info: http://www.teaflowergardens.com/growing-tea.html

Camellia seeds need to be extremely fresh or they will not remain viable. That's a cardinal rule. One winter, a friend sent me a couple of zip-lock bags full of freshly harvested seeds and moist fibrous sphagnum. His directions were to stick the bags in the fridge until spring, so two months later, I pulled the bags out and every single seed had germinated.

He had collected several pods from his extensive collection just as they were cracking open to spill their seeds.

The sinensis seeds germinate very easily, even if not just harvested; it takes 2-3 months to show the first small leaves.