I don't see how your regex can return the whole line as $2, because there are no +'s or *'s in there that can run away!

But I can help with the numeric part. You ask, essentially,

'12:08:19.17' >= '12:00:00'
[download]

And >= works between two numbers. Doing a string comparison (ge instead of >=) won't give you correct results unless the missing parts are padded.

—John