I think most Euro pears flower within a week of each other anyway. Winter Nelis is a prolific pollinator but not a heavy cropper. It is a good keeper.
john S
PDX OR

CHara

I grew some bosc pear from seed, and my seedlings did the same thing: One redish, one green with a slight red tint to the edges of the leaves and the trunk.

They do seem to change a bit as they get older. Also, seedling pear apparently can have spines...

Lastly - Dont expect to be growing the exact same fruit as where you got the seed. Our fruit have enormous genetic codes, which means the variability of the plants is really a guessing game. The odds are you should get something worth it, even for rootstock, but its very, very rare to get something really worth it from seed, and even rarer to get the parent.