Depending on the location of the branches on the Bosc, you probably should prune them back. If they are in a good position for scaffold limb then leave it. Honestly though, if it were me, I'd prune it back. Some others may disagree and I'm sure they'll give their advice as well.

For the other apples and pears the benefit for pruning down is to develop scaffold branches. I tend to prune my trees a little above knee heigh or between 2 1/2 to 3 feet from ground. Your trees will then send out the first scaffold branches which you will need to train to a good crotch angle and will also shoot a new central leader, which will continue to grow until you cut it back next year to develop the next layer of limbs. Training the limbs to how you want and what height you want depends on how far you want to go into the tree to pick your fruit. As Tom Burford says, "The scaffold limbs you train now will be what holds your future fruit crop for years to come".

Have fun with it, don't worry about it too much if you make a mistake. Pears and apples tend to be forgiving.

Thank you for the advice and encouragement! I found it odd that the company didn't prune the bosc to a whip and wondered if it had something to do with that specific pear not needing it. I'm wanting to give my trees the best start possible, not mutilate them with my shears:) So glad to hear they're more forgiving of amateur pruners.

I have Moonglow and Orient pears. I pruned them back when I planted them,and cut them back to 30". Now,a couple of years later, the scaffolds have been trained and I am awaiting fruit.
I have red and yellow delicious,Fuji and Rome apples,that I did the same way. My Peach trees have no central leader, are rather open in the center for better light penetration.
Seems to have worked out, well.