We got our two ducklings at 5 days old, they're maybe not imprinted but they bonded with us straight away, they follow us around and love being cuddled!
We're not too fussed with the distinction between imprinting and bonding, as long as they love us! Which they certainly seem to
Ours were factory farmed and kept in a barn with about a hundred other ducklings so it doesn't seem to matter that they weren't hand reared.
If you're only getting one duckling it's likely to bond more strongly with you, even if it's not imprinted. I'm so glad we got two though, they're incredibly close and it's so cute watching the pair of them together.
I think in the long run it's probably less work too, they settle at night no problem and can be left for about an hour at a time during the day to nap - I think if we just had one it would need constant attention to stop it being lonely or scared.
If you're able to lavish all that attention on one baby then I'm sure he or she will be a happily pampered pet

I'm just really glad we got two!
Here they are snuggled up together by the couch: