The watch case style is the first four numbers at the bottom of the dial. From your pic it looks like 7006. The second set of four is the style code. Using vintage Seiko production date lookup sites (don’t have the link handy at the moment, sorry), you may find pics of the original watch as issued.
The serial number contains an indication of the production date, the first digit will be the year (usually a specific year within the model’s production run), the second digit indicating the month. That might help you in finding NOS or vintage bracelets on flea market sites.