The original fluid for the Spark EV was 19300536.This was replaced by 19331925.
On 6/15/2018, it was replaced by two part numbers, 19417577 LV HP Dexron, which is specifically for the 8-speed automatic and 19369363 212B Dexron, which is specified for all plug-in GM cars, except for the Gen 1 Volt, which still uses 88865601 Dexron VI. The dealer I go to had all the current parts in stock.
I happened to run across a Tesla bulletin regarding noises coming out of the rear drive units on early S models and the fill on the bulletin is Dexron 212B.