I have found headphones Philips SBC3398, which look like vintage AKG 301. I was not sure about it, and headphones were very cheap, so I have bought them to make an evaluation. The headphones were in poor condition. I have made a disassembly and cleaning. Then I have taken a look on so many details as possible and compare manufacturing details with pictures of AKG 301 available on websites (forums/reviews). Philips SBC3398 look like rebranding of AKG 301 (only labels, printing and silver color of ring are different, rest of manufacturing detail are the same like K301). Drivers have got printed numbers 04 94 (date 1994 is suitable for AKG 301). I am not able to measure impedance, but resistance of single driver (103 Ohm) means that impedance cannot be 100 Ohm but it can be 120 Ohm (according to review of AKG 301 there ware two versions 100 and 120 Ohm). I was not able to make a regeneration with original Philips colors and labels. But I have refurbished with new pads, new headband, new ring, new labels (mostly based on parts printed 3D and silicone o’rings). Now the headphones look clean and are in good working condition. Some pictures before and after refurbishing have been attached.
Nice! They do look exactly like the K301s. The real question is how do they sound now that you have them cleaned up and working? I have never seen these before, but I have heard the K301s (the 120ohm version). I won’t try to describe them from memory because I’m not sure it would be very accurate. Either way, it looks like you did a good job cleaning these up.
Hi. Those headphones does not have huge efficiency, on volume knob need to be increased. Rather brigt then bass. You will hear bass guitar in “Money for nothing” but less then K280 or Sennheiser HD599. Also earpads are thicker and probably that is why vocals seem to be a little bit far from listener. I am not able to compare them to the sound before changes - they were unseable before.
Your description actually sounds like I remember the K301 sounding from when I had them many years ago. Very interesting! 
Thanks again for sharing!