You're correct in using class here.
I typically try to use class whenever possible and use ID's when I need to target very specific things for JavaScript targeting. For example, I may have a submit payment button. I want it to use the default button class I have set up, but I also want it to do something special in jQuery. I'd have my HTML set up like this:
<a class="button" id="btn-submit-payment">Submit Payment</a>
I wouldn't put any CSS for the #btn-submit-payment. All the CSS would be on the button class and can be used for anything. I would however target this element in Javascript to handle some onclick action. Here's an example of how I'd use it in jQuery:
$('#btn-submit-payment').click(function(){
// function to make the button submit the payment
});
I would not want to use the class because it would execute this function for all elements with the button class. For example:
$('.button').click(function(){
// cannot put the submit payment stuff here
});
So, to sum things up, I like using ID's when I need to use JavaScript for unique events and I try to always use classes for CSS. Some people may argue that using IDs such as #navbar will target faster than .navbar ... making the code run faster. I recall reading a study that tested this theory and the results didn't seem to make a difference.