ISO of rear OEM step for my ‘77. Based on what I’ve read it seems ‘74 and up would be compatible. Borrowed this photo from another post for an example. Let me know what you have.
I know you want the OEM one but if you can't find it, the City Racer step is really well made. I have it on mine and my twin girls love it. According to them, it is the best improvement I've made to the 40 since I bought it