+1 Right number of bearings?? One problem with reusing bearings, if there were not the right number in there to begin with, you will not have the right number after rehab. I made this mistake years ago. And its easy to lose a bearing (or two).

I opened up one bike, it had eight ball bearings on one side, and nine on the other (should have had 11 on each side....)

Now, I never reuse bearings, replacement bearings are cheap, and given that they are probably 30 years old if not older, its time to replace them. New bb bearings run me about 50 cents for a bb....

But by all means, check the cotter pin first!