mgriffin - If you are referring to the HTML Catologue Generator, MC does automatically convert product names into <H1> tags...if you are referring to regular dynamic cart pages, nope, we don't convert there.
As Captain stated, you would want to use <H1>, <H2>, <H3>, etc. from the top of your page on down to the bottom...it is a little risky to double-up on <H1> tags with the same text (ie, product names). Instead, you might try using larger font sizes, bold, underline, and/or italic attributes. Spiders love those...Appetizers to the main course (which is relevant content).

Of course, big font tags (like size 3, 4, and higher) aren't as easily - if at all - controlled with stylesheets so they can be less than aesthitically appealing, to say the least.
Hope that helps!
Jen