Not trying to belittle or discredit anyone Dave. Just offering some thoughts as to another possible explanation for what doesn't seem to add up about the bar in question.
As for Carroll. He never got to see exactly what he had found, other than signs it was a number of ingots of some kind, since his backstabbing "partners" stole it from him before he had the chance to dig them up himself. Can't make sport of him in any case.
If they were babbitt bars as well, then I'm sure that Carroll would have been amused to see the look on their faces when they found their betrayal had gone wrong, and the loot wasn't worth the trouble of hauling it to a scrap dealer.
Regards:SH.
if you are going to play detective then think about this...if those bars carroll's partners stole were babbitt....his partners would not have left the state and everything they own..they would have just waited until carroll got there and showed carroll the bars..these men left the state and were never heard from again...they abandoned their homes and possessions and got the hell out of dodge...which should tell you they were more afraid of the feds than they were of carroll..there is more to this story than i have said here