Some observasions based on some of the stuff I have in front of me, if it helps:
See the picture attached.
On the left is an 8000 power supply and on the right, a 5200 beacon power supply for comparison.
They should be close enough to illustrate a key difference.
The one on the left is "newer" and has a form of reverse polarity protection built in.
If you're lucky, your power supply is like this one.
On the right is an "older" design that had no such protection. If you're not so lucky, your power supply is like this one and the reverse-polarity damage could be extensive.
At some point Whelen added this protection in to this design. It's in the form of a big fat diode that would only allow current to flow in reverse. If this happened, the current would be sufficient to blow a "little fuse" while under normal running conditions, current flow would be under the little fuse's rating.
As you can see, I ran into this problem with one of the 8000 power supplies I got...as a "hack", I soldered in a single strand of wire. While I managed to get some 15AMP little fuses, I'm pretty sure the original was a 10AMP and I haven't got a hold of them yet so I just left the hack in place.
Note: the "newer" design has four integrated-circuits while the "older" has only one ("AE1-219"). There might be other variations along the way so keep an eye out for that!