If you are interested, just ask for more detailed pictures with a closeup of the inside of the receiver with and without the bolt in place. If he can't provide them in a timely manner, pass.
For some reason I have been getting free newspapers from a press that is normally subscribed to for months now. I give them to my parents every week.
We have 2 local newspapers, a daily and a weekly. The weekly mainly survives by printing legal notices, and you apparently have to have a minimum subscriber base to qualify a legal ad as a "public notice". My parents subscribed to it starting around 1978 or so, mainly because they knew the old lady that published it. A few years later they dropped it, but it has been delivered every week since! Every year I get a subscription renewal notice from them in their name, never return it, and it keeps coming... It has changed owners at least 4 times since they dropped it.