That a good setup they gave you. I would have to hassle with Classic Auto Air to swap bracket setups, exchange it for the one they gave you. I would also have to chase down a '69 and back original two groove crank pulley which is not reproduced. '69 and back small block pulleys are red headed step children. The idler in your kit may also need modding to work with '69 cast iron water pump. But your suggestion is good.
Do you have a part number for the bracket kit they sent you?