These shifters are rarely shot. Over decades, the lube turns to plastic, and the pawl springs can't push past this plastic. We remove the cover, put in some solvent, and wiggle the shifting pawls. In most cases, the shifter comes back to life once the plasticized lube is dissolved and the pawl springs have less plastic to overcome. I hope to see you Saturday.
Thanks good to know. I found a YouTube video that showed something similar but I haven’t really attempted anything on the bike yet.