I'm speechless about the price of those pipes. Some time ago I bought a Sanglas brochure from a guy and asked him wethet he had more that wanted to sell. He told me he didn't want to sell them directly, but to put them for auction and it would take about six months for that. It turned out he had something like 10 brochures in mint condition and was planning to "let them loose" on eBay every six months to start a bidding war out of the scarcity. I doubt that the pipes you bought were the last ones, but even if they werent, I once heard a quote by Sony president in the way that "you can always recover your money, but you cannot always recover lost chances".
My K1 pipes are HM300 stamped. Baffles are thinner than those, and those seem to have some kind of packing inside. Mine have no packing at all. Don't know whether they were this way from the start or the PO removed it to make them louder. What I have noticed is some run of grey paint from the drain hole almost to the muffler opening, not visible when installed, and I wonder what is that for. I'm pretty sure they came that way from the factory. I have just cleaned them now that they are out for the chain change. WD40 and fine steel wool makes wonders. Have a look at the pictures.
Furthermore, my bike is a K1 (feb 71) and it has the two hole rear hub. I never imagined it made it any special.
