Mine is a scratch build from original 1960s series plans.

On the CG... "on the spar" may not help much since the original and MarkII versions had a single central main spar -- you can't really tell right where the spar is once there's opaque covering on the wing. (I don't guess there's much need now that it's flown and checked out OK... but 1/3 chord should be a fine location for the Falcon's CG.)

Mag -- your plane is either a Mark II or later since it's got the reshaped fin adn rudder... and I'm thinking it's before Mark III because it's got the airfoil atabilizer. (That doesn't change the CG any because it's a symmetrical airfoil mounted parallel to the thrust line.

Fine, fine plane -- enjoy! (BTW, I have the plans (original version with the classic tail) if anybody happens to need them. I've been trying to keep the Falcons alive -- and now Lanier and others are helping.)