The top metal part can take a little pressure, after all it's fairly safe to scratch it with a screwdriver even (not that I tried
)... The shock could have damaged it though, with all the magnetic stuff going on inside there and what not. I'd say it depends where you got it from whether you should RMA or not. If they just replace it no questions asked then go for it. If they test the cpu and bill you $30 if they didn't find anything then... well, then still do it. You don't want to get your system ****ed just in case, because if you put in a damaged cpu it can be hazardous to your system.
P.S.: that's why I always unpack my stuff on my bed.