When Tim uses the sledge hammer to knock down the wall in the construction scene, he is swinging the sledge with his right hand near the top. When he loses his grip and almost hits Heidi and Al, the sledge hammer sticks in the wall. But, the gloves indicate that his LEFT hand is at the top of the sledge and his right hand out is at the bottom.
Randy gets irritated when Jill tries to tell him her "flute story". She told Brad the same story in "Slip Sleddin' Away" (S3, Ep13), then starting it off as "When I was a little person about your age", attempting to convince him not to give up on his saxophone lessons.
Tim mentions to Brad that he once got into a fight with his brother Steve for driving Steve's '56 Chevy into Quarton Lake. The lake, located in Birmingham, Michigan, a suburb of Detroit, was also referenced in "Unchained Malady" (S1, Ep19) when Tim tells Jill the story of when as a kid he was dared to jump naked off a dock into three feet of mud.