Lucky Pokemon

That' entirely up to you.

Personally, I wouldn't. Lucky junk is still junk.

But that doesn't mean it's junk to you. Has a 15 atk and if I can see some people holding on to it. But it's not a rare mon and better ones are typically much easier to find. Half the dust on an average IV mon is still a waste of dust to me.

I would keep it, at least long enough to see what moves they’re going to give Rhyperior. It has a very good chance of becoming a good investment at half the cost.

I sometimes throw low level lucky ones away (somewhat useless repeats and things I know I'll get again pidgey/rats). Sometimes I'll evolve those with less valuable candy to display the pokedex lucky screen, then throw them.

I'd keep this one for a month or so til gen 4 arrives. Also someday prestiging may return in some form, so you might not always want to use a maxed rhydon/Rhyperior. I keep lucky golbat, poochyena, and even duskull, etc with similar stats and level--so I'd keep a rhyhorn.

My storage is 1000, and I'm constantly gaining storage space--throwing 1 legendary a seems to help with that--I've traded legendary for legendary every single day since luckies introduced...no lucky.

Keep it, see if Rhyperior lives up to the insane hype, then decide whether it is worth investing in it (I think it will and yours isn't a terrible dustbin candidate)