another opinion to add to the mix.
i wouldn't call this coffin pleating (or draping). have you ever seen the old satin interiors of coffins? they're basically swagged.
View attachment 35695
this is this is coffin draping ^
i've seen oodles of old dry cleaners tags with those thick and wide staples, but never with a person's name written on them. they've always been printed, with a numbering system particular to the individual cleaners, for easy retrieval.
it does look late 30s to early 40s to me as well. the bodice is styled too early for 50s, and with all that fabric in the skirt, it says pre-wwii.