Can Rattata be shiny in Pokemon GO?

At the end of the Season of Mischief in Pokemon GO, trainers can catch a bunch of shiny Pokemon, including Rattata.

Shiny Pidgey and Rattata are now in Pokemon Go! – Aabicus Archives

Shiny raticate with hat :) : r/TheSilphRoad

Shiny Rattata

Pokémon Go shiny alolan rattata~ ! Will trade you a random shiny alolan rattata.

Pokémon Go shiny alolan rattata~ !~ unregistered OK~

Pokemon GO Shiny collecting - A complete guide

Second Shiny Alolan Rattata, still no Shiny Kanto Rattata. And 6 Shinies in 4 Days!

Pokemon GO Shiny collecting - A complete guide

7] Genuine question for Let's Go games: Is the Alolan Rattata we get on the NPC (Tatianna) trade at the pokemon centre in Cerulean City meant to be Shiny as standard? It's

Can Rattata be shiny in Pokemon GO?