While the actual shape of the blade probably is generally not unique enough that you could copyright it or trademark it I think that if you look at the overall picture it would land you in hot water fairly quickly. If your blades, handle materials, construction techniques, sheaths, grind lines, angles, and nearly every other aspect of the blades that you are making are identical to a product that someone else has already established you may very well find yourself in a legal battle that you cannot afford to win let alone loose. It would probably be better off for all parties concerned that you spent your time and money developing your own style instead of ripping off what another man has spent the last 30+ years developing. It comes down to taking food off of another man's plate, not honorable, not acceptable under any circumstance.