I think that depends on whether the gun has any collectible value or is in demand on the used market. I don't know anything about Berettas or the demand for older ones, so I can't comment on your particular gun. But let's say I had an old Python or Hi Power that absolutely needed to be refinished, I would try to replicate the factory finish as much as possible.
But let's say it were just an old Colt 1911 with no discernible heritage, a very nice gun no doubt but not collectible in any way, I would definitely have it cerakoted. It's around the same price, and it's a far superior finish in all respects. Much, much higher wear and corrosion resistance, and it also has a higher lubricity if I remember correctly.
As already stated, though, hard chrome or NP3 might be your best bet. You would just disassemble the gun yourself and send whatever parts you wanted coated to them. However, the nice thing about cerakote is that you could do it yourself fairly cheap, comparatively. A single color would cost you around 50 in paint, then all you need is an air gun and an old toaster oven. That also saves you the hassle of sending a receiver through the mail.
Another factor, though, is if this is a looker or a shooter. Is it something you're actually going to carry, or is it more of a BBQ gun? Whatever you choose, I would do the whole gun. It sounds like you've got bare metal on the slide and frame, which would be more of an issue than barrel wear.