I would say you have very little chance it would not.
Usually its newer versions of boards that have issues not older ones.
Also when there are issues with certain versions they would make annotations regarding it.
For instance:
#define BOARD_SANGUINOLOLU_11 6 // Sanguinololu < 1.2
#define BOARD_SANGUINOLOLU_12 62 // Sanguinololu 1.2 and above
but with the rambo it appears very straight forward:
#define BOARD_RAMBO 301 // Rambo
#define BOARD_MINIRAMBO 302 // Mini-Rambo
No versions are mentioned so I feel pretty comfortable saying it will work with any version up to 1.3 as 1.3 is over a year old and Marlin1.1.5 is only a month or so old.
Usually its newer versions of boards that have issues not older ones.
Also when there are issues with certain versions they would make annotations regarding it.
For instance:
#define BOARD_SANGUINOLOLU_11 6 // Sanguinololu < 1.2
#define BOARD_SANGUINOLOLU_12 62 // Sanguinololu 1.2 and above
but with the rambo it appears very straight forward:
#define BOARD_RAMBO 301 // Rambo
#define BOARD_MINIRAMBO 302 // Mini-Rambo
No versions are mentioned so I feel pretty comfortable saying it will work with any version up to 1.3 as 1.3 is over a year old and Marlin1.1.5 is only a month or so old.