Confusion with visa stamping


My petition A that was filed for FY2016 got approved recently and is valid until next year.

Meanwhile, my current employer filed a new petition B for FY2018. I’m yet to know the lottery result.

Can I go for visa stamping with petition A?

If yes, what if petition B is picked in lottery and gets approved later?

Yes, you can appear for stamping through A while B’s petition is pending or gets approved later.