Yup - we know that the incident took place just before Romulans went into isolation, and if the Treaty of Algeron has kept the peace for 60 years as of 2371, then it might be deduced that the isolation began in 2311. It would be odd for the isolation to start first, and peace to only follow much later... Not impossible, but odd. (A bit more likely for peace to start first, and Tomed to come later but, being an isolated incident, not count as an "actual" breach of peace.)
But 2311 is probably too accurate a date for the incident, as it would be something of a coincidence if the episode "The Pegasus
" took place exactly
sixty years after the incident, rather than merely approximately so.
Note that when Tomed is discussed in "The Neutral Zone" (the only mention of it ever), it is said to have been fifty years ago, even though "The Neutral Zone" and "The Pegasus
" are separated by six to seven years, not ten. So a date more like 2315 is probably a better bet.