It is cloaking it the lite skin is not the same default skin that you offer new users. Googlebot wants to see exactly what a user coming in from Google search is going to see. If you choose a different skin based on user agent, then Google may automatically detect this and penalize you. They sometimes make requests using a normal browser user agent to test for cloaking.
Regardless of whether or not it is cloaking, you may not want to use a different skin for googlebot. The contents that googlebot fetch are used to create preview images for your site. If you use a lite skin for goooglebot, your site won't look great in the preview.