Depends on what genetics were used to make the breed autosexing, but in general, yes.
I'm not familiar with the Smaaland, but from the pictures I see online, it's a barred duckwing. In that case, the cream legbars use the exact same genes to be autosexing, so their offspring would be autosexing.
You choose some sexlinked genetic traits that "stack" (two copies of silver will not make a chicken appear more silver; it doesn't stack, so even though it's a sexlinked gene, it's useless. Barring, on the other hand, does stack—roosters are lighter than hens, and as chicks, they have larger headspots because the roosters have two copies of barring. Fast-feathering and slow-feathering also stack, though there are some feather inhibitors that will hide that.) One you've selected your traits, you pick your breeding stock with them in mind, and mate them until you have a population with the characteristics you desire.
EDT: Autosexing can be improved by culling. For example, if you have the population you want, and they should, theoretically, be autosexing, but your barred roosters are hard to tell from your barred hens, pick the lightest roosters and the darkest hens and keep breeding. This will make it easier to sex future generations.
That's not a breed, and it's not autosexing. You're thinking sexlinked, which is slightly different (though it relies on several of the same genes).
Sexlinked = a gene that is on the sex chromosome. Roosters can inherit sexlinked genes from their mothers, but pullets cannot, such as in your example above.
Autosexing = a breed in which two sexlinked genes "stack" to make the males look different from the females. An example is a Barred Rock, where the males, even as chicks, are lighter-coloured than the females, due to the presence to two barring genes (females only carry one copy of the barring gene).
Sexlinked crosses are generally far more easy to sex than autosexing birds are, because, with the sexlinks, the males possess different colour genetics than the females do. 2x barring vs 1x barring is subtle, compared to 1x barring vs 0x barring.
