Nearly bought a pair of DM3 back in 1972, as they were the best B&W design after the DM70 with the electrostatic tweeter. But then a pair of Quad ESLs came along, and the rest as they say was history.

Yours look to be in great condition; but if you are intending on keeping the grills, I would paint the baffle black so as to disguise the outline of the drive units.