looks like a 1971 SL350 front fender, you have there. The SL350K0 had a 19" wheel, but that front fender was steel and mounted to a fair size tubular mount. The K1 had the same size front wheel, but had the front fender like yours & the K2 had a 21" front wheel and a mount like yours, but had aluminum front & rear fenders. Honda kept working to help their SL350 survive, by making a lot of changes to what started out as a CB/CL350, slightly "Looking" like a true Street and Trail, but ended up letting it go and bringing out the XL 250 & 350. Sorry, got carried away, with details (but I didn't cover ALL of the changes made over the years of the SL350.