Love at first sight - no. You can get an instinct about a person, something about them can just click to you when you first see them and it may be beyond or unrelated to physical attraction. My best friend of 8 years (also happens to be boyfriend of 4 years) and I had that when we first met. We just knew for some strange reason that there was something different about the other, that our energies just seemed to fit quite snugly together compared with other people and that we could trust one another with our very lives. We knew that from the start and time has proven us correct as we got to know each other over the years (an on-going process that still continues). But it needed that - time. The instinct was there from the beginning, but the romantic element took a lot of time. We didn't fall into romantic love at first sight, I don't know what it was.
You can have an appreciative love at first sight for a person like that as you would love a kind stranger, but I doubt romantic, otherwise it just becomes lust because you don't know yet what you love about them, and it's very much superficial.
If, however, you want to call that love at first sight, just having a knowing about the person you meet that they are right for you, I guess then it does exist. But in any case I very much believe it takes time, at least from what I've observed. I have known a few people who got into the romantic love at first sight mindset, talking about marriage only weeks after meeting and it never lasted after they took time to get to know one another more deeply.