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.
Nope, there is no official grace period with Pink OTC. You could call them and ask if they have some unofficial one.
Quarterly Reporting Obligations
In order to be considered as having adequate current information publicly available, issuers must publish Quarterly Updates to their disclosure statements through the OTC Disclosure and News Service, no later than 45 days after the end of each fiscal quarter. Quarterly Updates should contain responses to the following items, and should follow the format below.