I do not believe there is a 3DS version, I bought Risky's Revenge years ago but have only seen the DSi version I own in the eShop and no mention of a 3DS enhanced or VC version there. As others have mention, you will probably better off buying it on one of the other platforms unless you REALLY want to have it playable on the go.
At which point it might be better to wait a few months into the middle of the year to see if it along with other games gets a Switch port.













