Add pickup measure after the opening of a score

Hello! This is my first time using this forum to ask questions so my apologies if I’m in the wrong forum!

I am wondering if there is a way to add pickup measure within a score, after the initial pickup. I am transcribing a Mozart theme and variations, which has an eight note pickup at the beginning of each variation (K. 360). The sections are separated by a double bar, and have the same pickup as the beginning but in the middle of the score. I’ve inserted a picture of what I am trying to replicate! Is it possible to add such a pickup in the middle of the score without using key signature?