Yep! All tickets on SeatGeek that are part of the same listing are adjacent to each other unless otherwise stated in the seller's notes, which you can learn more about by clicking here.
Some venues, like theatres, may number their seats using odd and even numbers, making it appear that your seats aren't next to other. No need to worry, your seats will be next to each other even if the numbers aren't.
Other venues may have GA, or General Admission seating. Tickets to general admission events may have a ticket number assigned to them but it's common for these events to be standing room only. Most often, numbers assigned to GA tickets are simply for bookkeeping purposes.