1840 Large Cent - Should I Have This Professionally Graded?

I agree, surfaces appear to be altered unfortunately

Whizzing is done using a variety of metal, fiberglass, plastic etc. attachments on a rotary tool (dremel, drill, etc) to artificially enhance or create luster. Sometimes it's more obvious than others, especially if done poorly, but if done well is harder to notice without magnification. There will be hairlines visible under high magnification.

It usually leaves the surfaces flat a lifeless, as seen on your coin. There is no cartwheel effect to your example, with no rhyme or reason to the way the light reflects off the surfaces.

You can search "whizzed" or "whizzing" in the search bar and find a few good threads with examples.

I agree that it has the classic whizzed look

Looks like a Chinese fake.

Glad to see that you asked first, well done. I would agree that the surfaces are not original, sad, but even detail graded it would bring a bit more than one which is not should that be part of your question. To go that route I'd go with ANACS since their fees are cheaper without a membership fee. Still, it is a nice example all things considered.

NumisEd, just curious what you are seeing that gives the impression of a Chinese Fake. Is it the odd colored dentil? No disrespect meant, I am trying to learn to see what others see in spotting fake coins.

100% agree, like NumisEd I initially thought this was a fake because those surfaces don't look anything like an authentic piece. I still am leaning toward it being fake, the details look off.

I don't know if the details are off because it isn't genuine, or because it wore down a fair bit before getting whizzed. Either way, the details plus the surfaces are extremely suspect