It's not a bad coat, a bit dated though. I may pay a couple hundred not much more, especially since i'd have to get it vented and that can be costly.
It's very difficult to have vents put into a jacket that does not have vents.
This is because vents require a considerable amount of additional material as the sides of the vent should overlap each other so that the vent, or vents, do not gape open and show the trouser seat.
In short, whilst others may have different opinions and experiences, this is something that I would never try to have done. For a start, unless you are going to pull open the bottom seam of an unvented jacket before you buy it, you are never going to know whether there is sufficient material inside the jacket to allow you to have a vents (or vents) made. Chances are that there won't be and you'll be stuck with an unvented jacket.