concerns for my severe macaw

I noticed yesterday that my baby beak is turning grayish white. .. is this a normal thing or do I need to take him to a vet? He is approximately 19 years old

Just a quick look around the inter webs yielded malnutrition as a possible cause or systemic disease. Is the beak rubbery? Or is it flaking off? Can he still use it like normal or does he seem to be avoiding using it?

Portions of my Hahns beak turn grayish right before the top layer is about to peel.

He's using like normal doesn't seem to be bothering him. Feels normal to me

I've seen a few macaws with this grayish coloring in the beak, and I've not noticed any problems with them. I would keep an eye on it and if the baby exhibits any unusual behavior, lethargy, or weakness in the beak, get to a vet. What is the babies diet right now?

Pellets and a few peanuts during the day and then seeds, fruit and whatever we are eating for dinner

I just realized he literally isn't a baby. The pellet diet he is on, is that what the previous owner was feeding him? He doesn't seem to pick at it? Seems to eat it well enough?

Has he been having a particularly hard molt this year (many people's birds have for some reason). A lot of times, molting goes hand in hand with a little extra beak flaking (which is normal regeneration) and on a black beak, the layer thats about to chip/peel looks gray. My birds beak looked absolutely atrocious when he was molting in October (his molt this year overall was a rough one). It's back to a health, shiny, smooth black now.

Have you had him for all 19 years or did you adopt him? If so, did he have a good prior home or was he more of a 'rescue' who possibly had a poor diet? When was the last time he got a wellness check from the vet? I'm not a macaw expert but typically nutritional deficiencies present visually in the plumage, beak and nails, also in the energy level of the bird. He looks to have pretty healthy plumage. Are his nails overgrowing or has he been particularly tired lately? I think your going to see a big flake chip off where that gray spot is and that's all. You can take him to an AV for a wellness check if he hasn't been for a few years just to be safe

No I just got him in June (off a buy/sell/trade site) ... he looked rough when I got him. I took him to the vet when I got him and they trimmed and nails and beak. I think I'll take him in just to be on the safe side. I don't want something going wrong.

Make sure you take him to an AVIAN vet specifically, and request they do a full workup (which will involve drawing blood, physical exam and taking a fecal sample). Any new bird should have one just to see if there are any medical issues to address. The sooner a problem is identified, the sooner you can start treatment! He may be deemed perfectly healthy too, and then you know