I think this is a new question!
The timing of Nomad Camp has been discussed many times, unofficially. The conclusion has always been that it has to be timed as when-would-gain, or it can't change the gaining destination. The current official ruling about interactions between Nomad Camp and cards like Transmogrify also makes this unproblematic. So it seems to be: When you would gain a Nomad Camp, it first changes the gaining destination from your discard pile to your deck. (If you Transmogrify into a Nomad Camp, the gaining destination is not your discard pile, so Nomad Camp can't change it, so it goes to your hand.)
Accordingly, gaining Estate Inheriting Nomad Camp (without buying it), should not top-deck the Estate: It's not yours yet when when-would-gain triggers. But if you buy it, it's yours before when-would-gain triggers, so it should be top-decked.