Jalada (10/08): I'm not 100% sure, but I think...

Installing Flash Player 10 on 64-bit Ubuntu Linux (Hardy)

on tumble*jalada from 13 weeks ago

I'm not 100% sure, but I think you can just replace it. If that doesn't work, then remove the nspluginwrappers for the old version (using sudo nspluginwrapper -r <path> for all instances of it listed with nspluginwrapper -l), replace the libflashplayer.so file, then run sudo nspluginwrapper -i <pathtolibflashplayer.so> and you should be fine