Original Radios
To answer your questions :
yes , AM only .
Yes , the speaker is part of the radio as Joe showed in his pix .
Be aware than GM used a similar but NOT THE SAME radio in passenger cars so never ask " will this one fit my old truck ? " as the answer willalways be " yes it will " when it won't .
There's many places that rebuild them when you find an old beat up one .
I've seen them from $250 working to $1,100 fully restored , they can be easily converted to run on 12 volts when they're being restored or rebuilt .
Some places will gut and old dead one and install modern radio guts , AM & FM but retain the original looks , these are pretty neat and can be affordable .
For simplicity , Joe is the way to go as he can supply you with all the various parts & sundries to make it a painless installation .
Me , I lazed out and put a NOS German Blaupunkt cassette deck in my glovebox as I'm a German Car Guy and know those radios well ~ they work , no hassles , great sound quality if you use good speakers .