GEO. F.
VAN DEUSEN
1887 – 1910
The metal marker next to the George Van Deusen gravestone in the Woodland Cemetery in Jackson, Michigan, is a mystery. The handshake appears to signify membership in a brotherhood, but I can’t unravel what the meaning behind “MBA 841.” It seems to be a lodge number—perhaps. I also can’t find a reference for the letters “FLP.” Any ideas?
Gravely Speaking 
It’s Modern Brotherhood of America Here’s a badge with their logo https://www.ebay.com/itm/362616711501
I found this:https://www.ebay.com/itm/202449367875
The Modern Brotherhood of America was founded in Tipton, Iowa on April 5, 1897. One of its founders, and Supreme President for its first 22 years was Thomas B. Hanley (1852-1919), a former mayor of Tipton, as well as an active Pythian and Mason. Membership reached 130,000 during the period of cheap rates, but fell off in the 1910s as the Order attempted to institute actuarially sound rates and was hit by the First World War and the influenza epidemic. Nevertheless, it was during this period that the M.B.A. building was acquired.[2]
By 1923 the M.B.A. had 48,610 benefit members every state except the Deep South (Florida, Alabama, Mississippi, Arkansas and Louisiana) and Canada.[3] While the M.B.A didn’t mention anything about rituals or secrets in their propaganda literature,[3] they did have a ritual that was adopted at their Supreme Lodge in December 1901.[4] Officers of the order included the Supreme President, Supreme Vice-President, Supreme Treasurer, Supreme Physician, Supreme Chaplain, Supreme Conductor, Supreme Watchman, Supreme Sentry, General Attorney, and the Board of Directors.[5] The headquarters were called the “Supreme Office”. They also published a newspaper, Modern Brotherhood.[3]
[from the Pedia of Wiki]
https://www.buttonmuseum.org/buttons/modern-brotherhood-america
This is a link to the The Button Museum, an online museum dedicated to the history of pins and buttons. They have a button with this logo. Their description reads: The letters stand for “Modern Brotherhood of America, Fraternal Beneficiary Society,” which was a society organized and incorporated in the state of Iowa during the 1890s. it offered a “duofold protection” plan which covered life insurance and provided a modest savings plan for old age. The MBA’s headquarters were in Tipton, IA and Mason City, IA until its merger with the Independent Order of Foresters.
I hope this is helpful!