buy 2003 1500 sludge

Hi everyone, I have the opportunity to get a Ram 2003 1500 quad cabin 4wd 4.7 v8 for 4000$ it has 100k miles and some rust under it. heard that the 2003 4.7 has a lot of problems with the oil sludge thing, and when trying out I heard the engine 'clicking'. The idle is good, oil pressure too. Is...