We don't know if there will be a shutdown, but there are a few things you should keep in mind as a USPTO employee.
If the government closes at midnight on January 19th, you will not be able to work on Saturday or any time thereafter until further notice. To make sure you can complete your work hours for the pay period you should work your full 80 hours by Friday January 19th at 10 pm.
While the USPTO does have operating reserves, it needs authorization to allow its employees to continue to work during a federal government shutdown. In the past, the USPTO has gotten this authorization. There is no way to know if the USPTO will get authorization this time.
If a shutdown occurs and the USPTO is not given authorization to continue working, then employees will not be allowed to work (even voluntarily) or to use leave. If there is a shutdown, do not attempt to come into the Agency offices, or, if a teleworker, to use your UL without Agency authorization to do so.
Finally, for Patent Examiners, POPA will advocate for DM adjustments for all cases covering the period of a shutdown.