My experience is that this is not correct. First and anecdote, then the law.
My father failed to renew his CT pistol permit for a couple of years. Being a packrat, he was able to produce his NRA basic pistol course certificate from more than 10 years prior. It was accepted with a new application for a pistol permit by his home town of Branford, CT without exception.
This is as it should be since there is nothing in the statutes mentioning any kind of expiration period. The statute in CT is very clear.
CGS 29-28 No state or temporary state permit to carry a pistol or revolver shall be issued under this subsection if the applicant (1) has failed to successfully complete a course approved by the Commissioner of Public Safety in the safety and use of pistols and revolvers including, but not limited to, a safety or training course in the use of pistols and revolvers available to the public offered by a law enforcement agency, a private or public educational institution or a firearms training school, utilizing instructors certified by the National Rifle Association or the Department of Environmental Protection and a safety or training course in the use of pistols or revolvers conducted by an instructor certified by the state or the National Rifle Association, (2) has been convicted of a felony or of a violation of subsection (c) of section 21a-279
Don