In the last act, when the convict is fighting with one of the cops, we see the cop's gun fall out of his hand and land on the ground. But the very next scene shows the two men still struggling, and the cop's gun is back in his hand again.
At the end, the "Spindrift" is covered with dirt from the quicksand. Yet, in the very next one and all after, she is spotless. Considering the dirt helped camouflage her and the fact that they had numerous other more pressing matters, it's doubtful the castaways would have washed her off.