Hi just saw your message sorry I hadn't been on here for a while. Been busy working out of town. All 3 of my pair's if Dlk 4's are different and factory original. That's one of the main reasons for me buying the other two pair's of Dlk 4's. All dlk 4's are great! When fully functional I've never herd a bad sounding pair of 4's. The dual voice coils on the 12's is like having dual sub's vthey play/ hit harder great bass like the Alnico pair of 1978 Dlk 4's I posted pic's of. The bass is unbelievable and tight. But on those dual coil 12's they add a bigger 5" custom midrange along with a very tight quality high output Phillips tweeter to match up to the boasted woofer's. Very well balanced speaker's. They all are/were there top of the line and custom built just like your pair of 4's. Your Dlk 4's have the great Heppner drivers and EAS Tweeter's that sound very smooth an natural. Send me pics when your restoration is down I'd love to see them.