Double Bag Question

[tzme415]

This happened to me last night..Men's SP Rec League using double base..B1 hits ground ball to F3 who bobbles the ball then runs to 1B stumbling...F3 beats runner to base but steps over white portion onto orange bag..Runner comes behind F3 as he has passed bag..I call runner safe

Captain of defensive team argues, but very respectfully saying I was wrong and the rule doesn't say that the runner is safe if the fielder doesn't touch the white portion of the base. He wanted to know if the call was protestable. I of course reread the rule later and while it doesn't specifically say the runner is safe, it does say that the fielder must use the white portion unless the throw is coming from foul territory.

2 questions:

1) Did I interpret this rule correctly and make the right call?

2) Would this be a protestable call?