The early BK's had System 6 power supplies with the transformer in the head and the GI relay mounted in the head and not on the power supply.
The later ones had the relay on the power supply and the transformer mounted in the lower cab (like the other System 7's).
Because the relay is now on your replacement supply, the connector that used to go to the external relay needs to go to the supply.
Long story short, yep, change the connector. )