. . . or, you can . . .
Impakt Products has original LNBs for the dishes.
Just be careful which model you get.
They have single output, voltage controlled.
They have two output, where one is V and the other is H only.
And they may have more modern two output where either output can select either polarity.
On the elliptical dishes, you should retain the original feedhorn, since it matches the shape of the dish.
If your dish is round, aftermarket LNBFs will work (but probably not as well as stock primestar feed + LNB)
As another option, the FSS bandstacked Standard LNBs off DishNet SuperDishes will mate up to original feedhorns.
If you ask around, you can often get them for just a few dollars over the cost of shipping.
But, that's a whole 'nother discussion.