Can Heat Make DNA Unrecoverable?

Hypothetical question. Suppose a metallic object (such as a handgun) were to be baked at 450 F for several hours, assuming that the only DNA containing material was very thin like fingerprint oils, dead skin cells, sweat, etc - and not hard tissue or having a thick core such as bone - how likely would forensic DNA be recoverable? Also, if it could be damaged by this kind of heat, how long would someone have to save it and have a good chance of having typeable DNA?

Before anyone asks, no, I'm not planning a crime spree. I'm in college studying programming (we're using Microsoft XNA game studio) and my group was hoping to get a decent grade with a story that, aside from time travel, could be half way plausible.