Adorama and B&H Photo Video Do sell grey market gear, and they LABEL as such on the web page. They all sells LOTS and LOTS of USA market gear and label is as such. They are both good places to buy. KEH Camera Brokers is good for their used gear selection. They generally rate the shape the items are lower than most. A Good from KEH is probably at least an Excellent from other places. I recommend them all.
I think as long as you get a camera that lets you take control of the shutter speed, aperture, and ISO and has a lens that lets you get close-up, IF that is what you need for details pictures, you should be good to go. As others have said, knowing how to use the light, natural or man made versions, you can take darn good shots. I have a shelf in my closet FULL of older camera gear. I would like to get back into using it.