Bill:
I have three of these old Spotmatics. One of them was my first "good" camera and i think a lot of the line.
The camera and lens are probably just fine, the meter is probably not. The battery is only for the meter, and even if you had the cover and managed to get a battery that worked, the meter would likely not be accurate. And then, while there are substitute batteries available, the mercury batteries that are really needed are no longer available.
Someone may disagree, but I wouldn't jump through too many hoops to try and get the battery cover and get the meter working. The camera, on the other hand, should be a jewel!
Cheers,