Robert we compared the fork to a 404 and a 600 and it is about three inches taller overall and the bottom of the plunger is smashed much wider looking at it side ways where the axle hole is. The other plunger has a second hole drilled above the axle hole maybe for a break mounting. The throttle area on the handlebar can be seen in the picture and it doesnt have a square cut slot like I remember on the 4 horse. I think it could made to work on a 404 but it might be high in the front
I am going to stick with what I have until I find a 404 front end. Mine's the original one to the bike, and the forks are in good shape, it's just the right side handlebar has a kink and slight bend in it. Not sure how to deal with the kink.
Good luck on your sale, and welcome to the OldMiniBikes !!!