In this episode, Barnacle Boy states that he is 68 years old, which was indeed how old Tim Conway, the voice actor for Barnacle Boy was when the episode aired in 2002.
In "Mermaidman and Barnacleboy V", it is revealed that Barnacleboy, Man Ray and the Dirty Bubble all work at an ice cream shop, which also has an optional ice cream truck they can work in. This is evidenced 4 minutes into the episode, where Mermaidman orders a double scoop of prune ice cream with bran sprinkle toppings from the ice cream truck that the 3 E.V.I.L. (Every Villain Is Lemons) members can work in, aside from working in the ice cream shop itself.