Just after Rodney says "I can't even get my brush in it" a shadow of most probably a crew member is visible on the wall in the shop.
Just after Del says "I am not a cowboy" A boom mic is visible at the top left of the screen, but it is very close to the camera so it is quite large.
As granddad walks in with Trigger and says "It's Trigger for you Del" A boom mic is visible at the top left of the screen.
Shortly after Mr Chin walks into the kitchen to see Del, Rodney & Grandad a microphone can be seen in shot.