Unfortunately, it will not be feasible to remove the poster from its frame. However, it does not appear to be mounted to hard board (the frame incorporates a backboard, but it would surprising if the poster were attached to it). Our best guess is that it is linen backed or unbacked.
In terms of condition, the poster generally presents well. There is some light fading and foxing throughout, as well as a few isolated areas of loss and scuffing, particularly towards the left of the sheet. There is a prominent horizontal crease towards the top of the picture surface, with two fainter horizontal creases slightly further down on the image. Please see additional images available on request.