If i bought a ak in California now would I legally be able to remove the grip wrap and add a magazine lock?

I see no reason why not. But it can't be the old style mag lock. It would need to be a mag lock that requires opening of the action to reload or remove the magazine.
I don't know if such a devise exists for the AK.

I don't think it's possible for a mag lock to be created.

There aren't two halves like on an AR
You can't lock the bolt back (easily) for ejection port stripper clip loading things

If you really want an AK without going featureless, I would go for an SKS.

I have seen some home made designs on calguns, where the mag is screwed in from the inside. You have to remove the top cover, pull the bolt and piston out to load.

Personally I'd go featureless before going through that shit.

Exactly, that's what I was getting to. It's impractical as hell.

I still don't get why people are using mag locks on AR's. If you want to use it for anything other than range shooting you can't really do mag lock. I remember watching youtube videos of this guy who was in the CA militia and was doing Bullet Button reloading drills. I don't think that guy thought his choices through. You're not losing much by going featureless. I set my stock to one position and don't collapse it in, I can't tell the difference of not having a flash hider, and the only downside is that I can't wrap my thumb around my grip.