I'm not too sure what you mean by a hinge mark (I'm not a pro)... The stamp has no markings on it what-so-ever. The stamp is absolutely mint and has never been used.
Hinge is/was a little piece of paper w/ a bend in it (like a hinge) that they used to attached to the back of a stamp to the glue/gum then mount it ti whatever they where displaying the stamp on. When they take a hinge off it takes off a little area of the glue/gum off the back of the stamp. aka... MNH mint no hinge MLH / MSH mint light / slight hinge MHH mint heavy hinge the degree of disturbance to the glue if any is n, no s / l slight or light h, heavy.