When Dan reaches the service station and meets Choung, the pen markings that he 'draws' on his arm to show Choung what Richie's tattoo looks like are clearly visible before he even puts the pen to his arm.
In the beginning of the episode Dan goes back to 1975 where he helps McCleen who's stuck in a tree. But McCleen's parachute is of a model made 1979 or later. The parachute is connected to the harness with the 3-Ring system , which is a system that the skydiver uses to cut-away a malfunctioning chute. The 3-ring system was invented first in 1979 by William R. Booth.