That's a yes-yes. You're supposed to personalize the query for each agent, and some of them take that seriously. Why do you want him/her specifically? And they don't like you to say, Because you're breathing!, or I'm really desperate!
If you've got a ms. that reads similarly to one an agent's said she likes, you've got a way to personalize that query. Yay!
An aside: one very good agent asks why you write/why you wrote what you did. When I queried her I wrote a whole separate sheet of paper and did my best to plumb my psyche for reasons I write (and who even knows? Who even cares?) Later I read an interview with her--turns out she's just fishing for relevant experiences. So, for ex., if you wrote a book about the circus, and your name is Barnum or Bailey, that's something to bring up. She felt that a lot of writers failed to mention relevant connections between their life and work. But holy smokes, if she'd just said
that I wouldn't cringe every time I think of that query.
Editing to add: When Artemesia and I disagree, you should listen to her. She's goofy, but smart.
