Correct. Only 64 bit installs can use the Flow Storage DB. This DB is purely for the flow records. There will still be some info like the application mapping, IP groups that will be stored in the MS SQL database,i.e., 64 bit NTA installs will use both FSDB and MS SQL with the majority of the data being in the FSDB.
NTA v4.1 already marked the end of support for 32 bit installs