Any coil from a 2 stoke, single cylinder bike will work.
I was after a specific coil(for A bike), when I was told by a bike mechanic that any coil, as long as it was within a fairly wide range of resistance, would work fine- and it did. I put a DT175 coil on an RM 125 and it was business as usual. Electrics are a" Black Art". I have an old mate who runs a CDI from a whipper snipper on his Dad's very expensive Norton. And it works beautifully!