The Scottish and UK governments both seem to agree that state pension provision for current pensioners (and those reaching pension age before April 2016) wouldn't be affected in the event of a yes vote. The UK pensions minister told the Scottish affairs committee that those who had "accumulated rights" would be entitled to the same sum no matter what the outcome.
https://fullfact.org/scotland/pensions-independent-scotland/
https://fullfact.org/scotland/pensions-independent-scotland/