skibum - 8:33 pm on Aug 3, 2012 (gmt 0)
Generally no, but it has been a while but it depends on how much work has already been put into the campaign. The keywords would be really broad, the ad text not very detailed and the proposals designed to maximize revenue for Google and not maximize your sales. There was one rep that told us if we didn't run the proposal (on the content network) they gave us for a client, they would never give us another proposal for it in the future!
That being said it has been a while and it never hurts to see how someone else might promote your business. It is worth getting a proposal.