I would like help determining the age, rarity, and value of these speakers. The drivers are Hollywood 515 woofers, Hollywood 288b driver, N500C crossovers, horns are tar filled 1505 with brass throats. One woofer has the serial number of 6740. Cabinets are 612, they look like they have been painted black as the Interior of the cabinets are grey. Any Information would be appreciated!