I have wondered that myself. I suspect the answer is no in that they are physiologically well beyond being seedlings. I put a few Peterson pawpaws in full sun from the get-go and they didn't suffer unduly the first couple of years, but he sent pretty stocky and well established plants. My own experience (not universally shared) is that pawpaws in general prefer partial shade in South Carolina even as fruiting trees. My fruiting "Mango" in full sun always looks more than a bit yellowish and stressed. My partially shaded "Overleese" of the same age looks much better. Both are in the ground in sand, well mulched, and occasionally watered. Many others a few years old in pots are greener in partial shade. For the "Overleese" the "partial" is part of the day. For others it is dappled sunlight all day. The planted large pawpaw in full sun at Riverbanks Garden always seems a bit wilted. The native pawpaws several hundred feet away in the valley ravine forest seem much happier. I am going to request to see Clemson's experimental orchard this summer to see how a little increased latitude and elevation and decreased temperature and heavier soil may help.

You might want to rig up some type of shade cloth for them, or at least be prepared to do so without delay.
I lost an Overleese that didn't get enough shade.
Dan

Thanks for the info. This has me rethinking the location I have picked out. What does sun damage look like?

I'm in a similar position as c5tiger (pawpaws on order, looking to create shade w/shade cloth). Any recommendations out there on the type/brand of shade cloth to buy?

Sun damage will generally look like the leaves are bleaching, they will fade and start to turn white.

The reason is essentially thin cell walls in the leaves let too much light through and it burns out the chlorophyll.

If the plant the grafts came from was mature, I don't think you'll need to shade them, the leaves should already be able to take the light.

I can't find actual shade cloth in my area (even the nurseries look at me like I was speaking a foreign language), but I have been looking into some burlap weed cover down at Home Depot. Its a fairly loose weave burlap, looks like it would let some light through without being glorified erosion cloth.