The surface of meniscus lenses inside the camera will usually be dirty, the action of opening the bellows sucks in dust eventually to settle on the lens. Some lens cleaning access through the rear access port is possible with the camera closed. Cleaning the front surface of the lens is impossible since it is behind the shutter. The front element of VPK Special cameras lenses are easy to clean after their unscrewing and removal.
Vendors hardly ever say what type of lens VPK special cameras have. Lenses such as the Cooke, Tessar, Ross Homocentric and the Lacour-Berthiot Olor are rare and this makes the camera more collectable and valuable. Kodak and Rapid Rectilinear lenses are much more common.
Almost certainly dusty inside. With care the nickel plated viewing lens cover can usually be removed and a small artists brush or 'cotton bud' carefully used to clean the inner lenses and mirror parts.
These vary a lot. Some appear as brand new. Others have their outer finish flaking off and leak light everywhere. If you do not intend to use the camera then apart from close inspection appearance this is of reduced importance.
Fully opened, pre-autographic camera bellows were of a 'square' or 'box' construction and these seem prone to mis-folding on camera closure. Later cameras had pleated bellows (shown) which seemed to maintain their folds better.