They are covered, but you will not get replacement value, you will get far far less, especially for games that are not currently being made, which is like 98% of them.
If you are truly concerned about them, you need to schedule them, its not that much. I have all my games scheduled and covered separately from my home insurance policy. They required that I gave them a copy of the Mr. Pinball 2016 pricing guide, so that the underwriters could have something to base true market value off of.
Here is what to ask your insurance agent, let's say you have an awesome shape, HUO twilight zone worth roughly 6500-7000 in value. Ask them if that machine gets destroyed or stolen, will you be able to claim that full 7k and get it without hassle under your current home owners policy? I bet you find the general answer is no for that specific scenario.