If you go to edgar and click on most recent filings (all companies), there are filings accepted and dated today (for other companies), so I assume that the filings process is still up and running. It is possible that those filings were submitted before the shutdown and no new filings are being accepted, but I doubt that since I doubt that the recent filings would have taken from before the shutdown until now to be accepted.

So short answer is I don't think it is the SEC holding things up.