No.
Example
The bfs_nr 3955 belongs to the municipalitiy Landquart (GR). Until
October 1977, this bfs_nr 3955 was also in use but for different
geographical entity, namely the “Gemeindefreies Gebiet
Maienfeld-Fläsch”.
Consequence
To join two datasets of two different time periods, one might think
that the bfs_nr can be used to do the join. However, this is not
possible because the bfs_nr can be reattributed over time. Thus, a
simple bfs_nr based join is not possible.