I reckon that 10% of my punts have been with a WG with fake tits. I can't say I specifically seek them out or avoid them, but rather look at the whole profile. What I have found though is that on the whole a WG with fake tits is more towards PSE than GFE on the scale of things, perhaps a confidence thing, perhaps their background, don't know.
I can't imagine many of those with natural tits, even small ones, going to the trouble of getting them inflated, or even being organised enough to do so. Besides, they moan on about wrinkles, cellulite, a single grey hair and fat arse much much more than having inadequate tits.