My take on the fuze isn't that the Israeli's copied it, but rather procured it from Germany. They then ink-stamped their abbreviations for the delay settings over the original markings. I would think that if they bought production rights from the Germans they would have stamped their own markings into the fuze body during manufacture. Like was mentioned before it isn't all that uncommon for a country to buy ordnance from another country. Often it is a lot cheaper than setting up their own production line and doing all that is required to design and produce the item. Especially if the demand for the item doesn't mean large quantities or long production runs.