Timely buyer.
You should tell the seller that, you will consider and check the camera shutter and test it by computer. It means the camera should be in high quality at all. In this way, I have to coniisider to set the selling price higher instead.
Too stong in keeping the price, even the camera is not a small problem. Actually a spare part was missing which has not mentioned in the post. Anyways, I am happy to own a FM2.