Could an old universal dock damage the battery of the iPhone 3GS?

I have an older Apple dock (model A1153, output 3.3V according to what is printed on the bottom). I cannot find it listed anywhere on the Apple website.

I briefly inserted my iPhone 3GS and received the message that this accessory is not made for iPhone and do I want to turn on airplane mode.

Is there any possibility that charging/syncing my iPhone in this dock would damage the battery (or the phone itself)?