If you open an RM database with the RM program, then the RM program will write into the database even you never change any actual data. You will not be able to look at the data with the RM program unless the RM program has read/write access to it.
Robert's suggestion to make a copy that you mark read-only is your best best. Then you can look at the copy that's still marked read/write. If ever you change it by accident, you can then delete the read/write copy, make a second copy from the read-only copy, and mark one of the two copies read/write again.