Yes it does have the additional wire, but from what i was told, the antenna signal comes through the RJ-45 connector that attaches to the phone in the center console.
From my research, I found an adapter kit to integrate to the OEM phone. It can be located here: under cellular kit.
However after calling the company, They advised me that the kit is no longer in production. Basically demand was not great enough to sustain production, quite a shame actually because it would make for a really nice integration.
My phone is installed. I made my own custom mounting bracket that puts the cradle just to the left of the head unit. Notched out a corner of the cassete holder to run the wire behind the dash, and went with an antenna specialists on the glass cellular antenna. So far no signal problems whatsoever. I will post pictures of the completed install as soon as we get a decent day and there is some sun.
Next step - speaker upgrade, The OEM speakers are terrible, but they will do until I decide exactly what I want. I am thinking a component set in the front and 6.5 coaxials in the rear, and possibly a small sub. We'll see.
Thank you for all your help
Best wishes and take care -