At the beginning of the episode, Colonel Potter dates the letter he is writing September 26, 1953. The episode was aired September 26, 1983.
Colonel Potter is offered $12,000 a year for the post of Chief of Staff at the VA hospital. In 1953, doctor's salaries ranged from about $11K to $15K, so this is in line for a doctor in a semi rural area at that time. In 2022 dollars, that salary would be just over $133K, while 2022 Chief of Staff salaries range from about $225K to $340K. Again, this makes Potter's salary reasonable for a VA Chief of Staff in 1953.