Constable Wade spent the rest of his life with the bullet lodged in his stomach next to his spine.
Coronial inquiries cleared Mr Wade on any wrong-doing and said he had no choice in hitting Evans.
Ms Carroll said that over the last 100 years, Evans had become a "folk hero" to the New Zealand Federation of Labour.
"They have honoured his death every year."
She said the police exhibition was to recognise Mr Wade and the work he did on behalf of the public and police.
"We thought it was about time that the police side came out."
Included in the exhibition was Mr Wade's baton, gifts presented to him by police for his work and his gramophone.
Mr Wade's grandson, David Walker, has written a book on the incident, Shades of Black, and that will be launched tonight at the museum.
Those attending include Walker and other Wade family members, the Police Association, the Police Executive, members of the police and the Waihi community.
The exhibition will run for about six months.