Whether there is too much oil in the system is not really important at this point- the fact that the leak has not been taken care of is more important. The AC system is a sealed system under as much as 275psi on the high side. When there is a leak in the system that goes unrepaired, the rest of the system weakens over time, and one the initial leak is finally repaired and the weakened system is now put under renewed pressure again, other components of the AC system generally will fail within a short period of time.
The excess oil can be evacuated from the system with an AC evac and recharge machine.
***Do Not use any AC leak sealant product on the market- it will gum up most of the components and create blockages in the system. Also, if you have installed this into your system and do not make a shop aware of this before they evacuate the system with their machine, you can be held liable for damages to the their ac machine due to it gumming the machine up- these machines are in the $5-10,000 dollar range.