Non Meteor Mash Metagross

No.

It's not worth spending any resources on a Flash Cannon Metagross; Steel isn't that great of a Type right now, and what makes Meteor Mash useful is that it is literally Flash Cannon for half the energy, so you can spam it with STAB. (and for those of us in the Northern hemisphere, we're getting to the point where it's going to be STAB + Weather Boost.) Flash Cannon is literally half as good as Meteor Mash - don't waste Beldum candies or CTM's to try to get it.

If you've got "Good" Beldums, keep them around (if you can) in case Niantic does a "Now you can get all the CD Moves for these Pokémon!" sometime in the future, in a similar way to how they put Mewtwo into general Legendary Raids for a month when they removed it from the EX Raids. Or maybe we'll get a "Metagross Day" like we got Gengar Day, and on that day we will be able to evolve Beldums into Metagross. Personally, I've got 10 high IV or Level 35 (Beldum day was Weather Boosted for me) Beldums taking up space in my inventory on the hopes that this might happen.

In the meantime, the best thing is to try to find someone to trade with.

I'd hold onto your good beldum for now, flash cannon inst that good of a move and steel doesnt have many match ups aside from togetic raids which only meteor mash metagross are able to handle with friendship bonus for duos. I'd recommend looking for someone with a spare

Its possible niantic might rerelease meteor mash in the future, I have a friend who did beldum swap after the event for candies, got 2 perfect luckies, and I dont think that's an isolated incident, its possible niantic might rerelease it in the future, or perhaps a different special move for metagross like what happened with Gengar

Trade for a meteor mash. It's so much better.

I have a couple of my original Metagross with double psychic moves and he is pretty decent to drop in gyms as a Machamp counter, or for soloing a Machamp raid, so if you can't trade maybe think about that as an alternative use.