E30 Zone

Some vandal recently snapped off my manual aerial (rear wing mounted) and I am considering an electric replacement.

I believe GSF do BERU ones for about Ԛ£25 but my question is:

Will my car already be wired for an electric aerial (1989 318i 2dr)?

If not, what wiring is neccessary?

Thanks

ALL U NEED IS A POSS , POSS FROM HEAD UNIT & GROUND SIMPLE AS THAT