The history of the church at its website records the destruction of the church by fire on February 25, 1959:
But in the early morning hours of February 25, 1959, fire totally destroyed the Chestnut Street church. The only thing to survived [sic] the fire was the church tower bell, which now sits outside our church. But the members and leaders were determined to rebuild. And in October 1960, a new church was constructed on the same site.
The destruction of the organ in the church was reported in the April 1959 issue of The Tracker:
Church fires have taken a bad toll of tracker organs in Massachusetts recently. Gone are the 1877 Hook & Hastings in Gardner's Methodist Church, and the 1886 Hook & Hastings in St. Matthew & Redeemer Episcopal Church of South Boston.
“Notes, Quotes and Comments,” The Tracker 3, no. 3 (April 1959): 8.
“Our History,” Gardner Chestnut Street United Methodist Church, accessed July 22, 2020, https://gardnerumc.org/about-us/our-history/.
Identified from company publications as edited and expanded in The Hook Opus List 1829-1935, ed. William T. Van Pelt (Organ Historical Society, 1991).