Sorry, I really wanted to post this question here because others might ask the same.
I bought a EOTech 551 on eBay costing roughly the same as what you paid for your china replica 552. For those of you who don't know what the 551 model is, its the same as the 552, but only with a smaller battery compartment.
Anyways... my question is how can I know for sure if it is a replica? All the clues you pointed out in your "real version" match mine. Its even got the "for law enforcement/ military use" written on the side.
Perhaps a serial code somewhere?