Depending on the stamp issue, the stamp size, and sheet lay-out, some guide lines are perforated and some are not. Some guidelines are cut and some are not. It differs with each issue.
In the case of the Panama Pacific issue, you are correct, the guide lines are not perforated and all panes are cut along the guide lines. The image from the original poster has had the perfs added at left and top. Although the original stamp shown is a perf 10, I got this perf 12 example on cover at a show earlier this month specifically because it showed the unperforated guide lines:

