Reversing a battery?

1980 delta 88 olds, battery flat dead, several months. replaced it to start and move it. Took original battery and charged it. When we reconnected it BOTH side posts sparked BIG TIME! hooked it up anyway. car dead except for headlights burning fine…nothing else worked. Towed it to repair shop…they said that the battery had been reverse charged!!! is that possible? can that happen?..said bad module and he would reverse the reverse charge…he thought he could anyway…

IS ALL THIS POSSIBLE???

Don Hughes

donwy2aol.com

just googled your question…got this web site