Yes, although I'd argue that it's not meta-hipster but meta-geek. If you wouldn't use 'grok', you probably wouldn't use 'eir'. In the same vein, putting your punctuation outside your quote can either be a simple mistake or meta-grammarian protest. Even the choice of single versus double quotes is signalling, consciously or not.

The problem is not correctness, but whether the signal is properly received by your audience. You chose 'his or her', but was this a conscious choice? And at what level? Was it because you fear being judged poorly for the grammatically correct but non-politically correct 'his'? Because you find 'eir' pretentious? Because you find substituting 'her' to be an affectation?

To me, 'His or her' is a signals that you are aware that language can be sexist, and want to show that you are not. I think it correlates with college-educated American liberal born after 1960, or one who has learned his English from such.

I fit these characteristics, but usually consciously choose 'his', hopefully signalling that I detest linguistic contortions for the sake of signalling political correctness, but more likely just being judged an unrepentant sexist. If I don't want to take this risk, I switch to an across-the-board 'her', as I feel this is more effective at actually combatting sexism.

Have you read Hofstadter's essay on "Purity in Language"? http://www.cs.virginia.edu/~evans/cs655/readings/purity.html