do new 38-357 rcbs dies come with round nose and flat nose bullet seating stems? thank you

Not sure about RCBS, but my Lyman carbide Set does.

I think so but not sure. I do know that the Dillon dies do,with a pull pin to drop the seater stub to clean out lead deposits,etc, w/o removing the die.That in itself is a great selling feature,especially on my progressive 650 press but is still applicable on a single stage or rotary press as well.Any time not having to reset a die is a boon.

thank you

YES