Unless you have
travel agency access or a paid commercial service that lets you see actual inventory (like Expert Flyer), that's probably not an accurate statement. You can't use seat maps to judge the number of tickets sold.
Lots of times, people don't bother getting seat assignments in advance. According to the dummy booking I'm making, it looks like Silver charges an additional $8 to pick a seat. Personally, I wouldn't pay that considering the size of the plane. Every seat is either a window or an aisle. Since I wouldn't get stuck in a middle seat, I wouldn't care and therefore wouldn't pay extra.
Silver Airways is a commuter airline that gets a decent amount of business travelers. Generally speaking, business travelers don't book travel in advance. Your trip is about a month away. I would imagine that your outbound flight (an 8:40am departure on a Monday) will start filling up about 2 weeks in advance.
(I used to work at a business hotel. It was quite normal for us to go from 70% occupancy to 100% occupancy in the two weeks prior to a week night. That's when business travelers would finalize their schedules and book reservations.)
Personally, I wouldn't worry. Even if it is a sparse flight,
Shelly F - Ohio is correct. Airlines almost never cancel a flight because they need both the plane and the crew to be at your destination for the next leg.