No, it's not at limited capacity to the extent we can tell - GF3 and all local Chinese suppliers of them got permission from the Shanghai government to start up on February 10th already - i.e. they had three full work-weeks in February already.
Here's a video that shows the GF3 production lines humming, reportedly at full capacity, a week ago:
The report mentions that Tesla hired 600 more workers - very likely the second shift. The Shanghai government also freed up several office buildings near GF3 with over 500 separate rooms so that Tesla can move in and isolate workers better, as a precautionary measure.
They also mentioned that the district GF3 is in didn't have any coronavirus infections. The last new infection reported in Shanghai was reported 8 days ago, on February 20.