No security cable on my radio. I suppose it's possible the antenna wire or the radio wiring harness is hooked behind something... had no problems pulling mine. New radio should slide right back in and lock in place if it's the same type/model.
BTW...more than 3 months since applying the rubber...
For months my wife and I had been beating on the radio to make it operate but that method no longer worked so I decided to pull it and have a look see. Several threads here alluded to the methodology needed to achieve extraction but none that I could find were precisely specific to the 5 hole...