Are you kinda out in the country/rural area( can you see DC from there?) lived in Alexadrania? for a while I was based at DC in 1969-------

Most obvious would be probably if it has an external front dampner it will be external balance ------IF it has a neutral balance front, chances increase to it have been balanced internal and would need a neutral flex plate.

Its sorry circumstance but seems that the people that balance cranks are all wierd in there ways/methods-----thats why I have my own balancer.

just so you know-front dampners can be either the outr ring or the internal hub that is offset balance-take some close up pics and post them--the heavy weighted portion will be 180 from the offset on the rear crank flange----