An actor is seen wearing a Butthole Surfers t-shirt featuring the 'Cowboy Bob' logo. While the Butthole Surfers are certainly around in 1985 and certainly present in the Dallas area, that logo was not created until 2002 by Fort Worth native King Coffey, Butthole Surfers drummer. Butthole Surfers lead singer, Gibby Haynes, was born and raised in Dallas and his Father is none other than 'Mr. Peppermint', Jerry Haynes. Jerry Haynes was the Dallas area equivalent of 'Captain Kangaroo'.
The Atari 1027 printer would not work with the Commodore 64 or Atari 520ST. The Atari 520ST was not released until June 1985. GEnie was not founded until October 1985 (this episode takes place in March 1985... maybe April).
Gordon is using the second edition of the book The C Programming Language which wasn't released until 1988.
The nurse taking Gordon's blood pressure would never have done it on the same arm as a blood draw, that can cause bruising around the puncture area.