Jake53,
The system is charging, although it looks like the max voltage is higher than it should be. As I recall, it should cutout around 7.4-7.6 volts.
The ammeter is a pretty dumb instrument, it is only showing you current flow through it, and I would say it is obvious that it is connected backwards.
The tests you performed show that the generator is functioning, and that the regulator is "regulating", just a bit high.
Your meter could tell you state of charge of your "toasted" battery, but wouldn't indicate if it were any good or not.
If you installed a new 6 volt battery, you want to make sure the system isn't going to overcharge it. If the battery compartment was full of acid stains, or the old battery was out of water and wet on top, this might be an indication your system has been overcharging for some time.
The regulator is made to be adjustable. Usually this is done by someone well versed in the procedure...no nose ring or pink hair!
The alternative to adjusting is to replace.
You might want to take a look at the Tech-Tip section. I think there is a good article on the 6 volt charging system compliments of Hot Rod Lincoln.
I guess you have made sure your battery connections were based on the positive and negative notations on the battery case and not solely on the color of the cables.
Stuart