No, it is but a poor approximation of Θώθ, the Greek name of the Egyptian God of Wisdom. Unfortunately most keyboards cannot type the language of the gods, so we poor mortals must make do with OwO.
(/s. It might have started among furries but is pretty much a meme at this point.)
I did meet a lot of gays and furries (VR Chat player) and I don't think they have any dog whistles. OwO does indeed helps them recognize people that don't hate them, but it isn't meant to be unregonizable by bigots.
It's more of a opposite, people saying OwO want to be obnoxious. Saying it is either a show that one doesn't mind being seen as gay/furry (and isn't necessarily), or straight up wants to annoy someone.
Not everything's funny to everyone, man. Maybe it's just not your thing. It basically just implies you're horny and want to fuck whatever you're talking about. Or personifies an object as horny, as in the image.
If O_O is a normal surprised face, OwO is an animalistic surprised face. That's the origin really. Anything else is just contextualization and Internet phenomena.
"Oh man that's a big cucumber O_O" sexually implied sentence.
"Oh man that's a big cucumber OwO" sexually implied sentence, but furry.
Started out as a furry thing, think it's been taken up by weebs now as well. Not sure if it's non furry weebs tho, as you might imagine there's a bit of overlap