If you are trying to determine whether you need to replace the top end, I would also advise having the piston measured up as well.
Compression test will only give you some of the story. A new set of rings on a old flogged piston will give you an accpetable compression reading, even though the piston is about to drop the skirt. As sachs mentioned.
And if you replace the piston also replace little end bearings and pin. The whole set up is only as strong as the weakest link.