Is it possible to filter those files by using the mentioned part of the filename (convert it into a timestamp) and compare it with the current date to find out which files are older than 2 years?
OK, since there is obviously no filter possible, maybe an alternate approach.
Can I do some (JS-)scripting to extract the date from the filename and call TOUCH (presumbly DO provides such a command) to change the file's modification date (leave the time as it is)?