Looks pretty close to me. I have no idea, though, if it's still a valid pattern number. You'll have to check that out.
http://vintagepatterns.wikia.com/wiki/Simplicity_7407
Here's the pattern on sale:
http://www.artfire.com/modules.php?n...duct_id=956934
Looks like it's called a Jiffy dress in the toddler size but the adult Simplicity "Jiffy" dress is a totally different pattern.
http://susanscloches.blogspot.com/20...-finished.html
It doesn't look too complicated (only 2 pieces). If you're feeling a bit adventurous, maybe you can buy the child's pattern just to get an idea of how it's put together, and then draft your own pattern for a larger size.