BooHoo

[78F350]

... Since the battery is already dead can I go ahead and disconnect the battery so I can charge it and get the car to running? ...

If the battery is dead, there is no urgency about the radio code. Go ahead and get the car running as soon as you'd like. The "code" is just number that you enter into a stock/factory radio any time that power had been interrupted. It is just a security measure for the stereo to make it less desirable to thieves. Until the code is entered, the stereo will not work, that's all.

Edit: If your car came with the original stereo and manuals, the code should be noted in the manual.