Maybe the K stands for Kaputt. Trace Elliot Facebook group has a post from an Auction purchaser. He got two later Ah 12 band heads, one has a sticker with that very word inscribed.
Apologies if this has been pointed out before in this thread but I'll compound the heresy.
There's a TON of Tonewood Guff on the MTD Basses posts on F/Book lovely instruments tho they are.