Although it's never identified by name in the story, the establishing shots of the prison are of San Quentin prison near San Francisco.
An accurate prediction in the "future" room of a large screen flat panel color TV which didn't exist in 1968.
After Barret is "revived," Roland Hand, posing as Dr. Moore, orders 5cc of Cordrazine. Cordrazine is a fictional stimulant from Star Trek (1966): The City on the Edge of Forever (1967), also a Desilu production.
The script was based on the concept of cryonics, the low-temperature freezing and storage of human remains with the speculative hope that resurrection might be feasible in the future. It was first performed in 1967 on Dr. James Bedford, who still remains in cryostorage at Alcor Life Extension Foundation.
When Barret is in the Specialist Doctor's office he notices a magazine on the rack from Newsmonth, a play on the magazine Newsweek.