I was a cub scout from 1977-1982 and moved up to scouting, receiving my Eagle award in 1987.
I too learned the "interlocking pinky" handshake with the RIGHT hand. Along with the secret OA handshake. Lol
I never learned the LEFT HANDED handshake until now that my son who is joining the Weblos rank.
As their Den Leader, I will teach them both, even though the left handed grip is what's discussed in their handbooks.