I have actually been testing it half unupped, though to be exact only the sparks and Afla were unupped. I'll check completely unupped soon
If you got all cards but sparks (that is, SoPa, SoSa, pillars, arsenic, and aflatoxin) upgraded, the deck should work identically as the fully-upped one anyway (since the Ball Lightnings were meant as Afla sacrifice).
I'd like to test it unupped myself ... if I have two more SoSa ^^;