D'oh! MacBook got a speed bump from 2.26 to 2.4 GHz a week after I purchased one at the Apple Store. 
Skinflint that I am , I searched the web and discovered that one can exchange for the newer model within two weeks of a purchase, but after paying a 10% restocking fee. Further, there is anecdotal evidence that a store manager can waive the fee. So, I called the store and asked. Yup, gotta pay the restocking fee , but hey, the remaining stock of the older model is now $50 less and they can refund that. Ding!
The exchange/refund policy was news to me, even after 25 years of Mac use, so I pass it on to the community.
 In spite of my usual due diligence, searching the web for rumors of such an update.
 I know, a real skinflint would have bought a refurb or Amazon unit, but time had precedence on this purchase, so I paid full-freight at the store.
 I didn't press on waiving the restocking fee, but suspect if the speed bump had higher priority than the fifty bucks, I might have been successful if I had.
Before the Apple Store existed, individual resellers had their own policies. The 10% restocking charge was in place since day-one of Apple Store's existence.
Generally speaking, computer products' update cycle is anywhere between 6 months and 9 months. The MacBook was updated 10/20/2009, so the 4/13 revision date makes it just shy of six months. For the MacBook Pro, it was a no-brainer. It was updated 6/8/2009 and by 4/13/2010, it was like a bad pragnancy - nearly ten months.