Good find!!! I would venture that your theory of manufacturer supplying others is probably not far from truth..... That looks too similar!
I found some Carello relays on some Italian car in the junk yard years back, but found that one was a "NO"= contacts "normally open" and one was "NC"= contacts "normally closed".
Some relays, like the small cube Bosch types may have both options are are great substitutes in a jamb or as spares.... But the Carellos seem to be one or the other!
So, buyers beware!!!!
I like the circuit on the plastic to "explain" how to hook it up!!!