Certainly there is no 6 month grace period with the SEC or with the OTC BB.
With the SEC there is a 15 day grace period but only after filing an NT10Q advising of a late filing.
There is a 30 "grace" period with the OTC BB, but during that 30 days they get an E appended to the symbol, then if they don't file within the 30 days they get bounced off the BB to the Pinks.
Also with the BB, they have "3 strike rule". 3 late filings in a 24 month period and a company gets bounced back down to Pinks.