Sorry you didn't get a nice sample. The P226 I just got was pretty worn on the right side too. Rubbed against seat belt, bumped into everything I'm sure. New grips will freshen that up rather cheaply. Remember, these trade-ins often just sit in a holster, bumped into everything, rained and snowed on during traffic stops, just put through hell but typically not fired much.
The DAK...I never got it. I understand how it works, just not why anyone would want it. As bad as the condition is, maybe a detail strip, clean, fresh lube and re-spring will help. There may be French fry salt in the action. I only sorta kid. I find it hard to believe any stock SIG trigger could be worse than a stock HK trigger.
If nothing else, sell/trade it for something you might enjoy more.