The 1950s was a time of high-fashion and the doll clothing of this era reflects this.  Most collectors look for original 'factory' clothing.  The fifties was a time where moms made doll clothing for their children's dolls and doll patterns were very plentiful.  You could find a variety of doll patterns for virtually any doll from the 1950s.  Here are some general guidelines for determine if a doll garment is factory:

1. Tags.  Some companies tagged their outfits so this is the most obvious sign of a factory outfit.  Madame Alexander always tagged her clothing. As a footnote, she also made separate clothing for some dolls. They will be tagged "Madame Alexander" along with the size of the doll.  It will say "Madame Alexander 18" inch doll".......etc.  Ideal tagged some clothing especially if it was attached to a patent such as the "Toni" doll which had to pay royalties to Gillette.  Vogue tagged their clothing, Artisan tagged some which will be tagged "Michelle", but the majority of doll companies did not tag their clothing.

2.  Seams.  Look at the inside seams.  If the seam is "serged" it is likely factory.  The waist seam will have a finished look with a factory zigzag which is a "serged seam."  Moms didn't have the machine that could serge seams as they were not on the standard sewing machine.  After the tag, look at the inside seams for the way the inside is finished.  If it is serged, it's likely factory.

3.  Closures.  Look at the way the garment closes.  If it is a gripper snap, it's likely factory.  A gripper snap is a machine-applied round snap that is not sewed on, but put on in a factory.  There are small solid metal gripper snaps, often painted white - as well as donut snaps - which will be a round snap with the fabric showing in the middle.  Snaps and buttons are a little trickery as they were accessible to moms.  Square snaps are more often factory, Madame Alexander used square snaps, as did American Character, Arranbee, and Ideal used them on their Shirley Temple dolls.  Common round snaps were not generally used in the factory.  Buttons were used by doll companies such as Ideal on their Tonis, Saucys and other dolls.  The button is a round white button with a slight swirl.  Moms used buttons too so look at the button holes.  The factory button holes will have a more "finished" look.

4.  Fabric.  Certain fabrics were used extensively in the 1950s.  As a footnote, these materials can still be found on the vintage market, and modern seamstresses can make these dresses for the resale market.  I have found these garments to be wonderful reproductions, they usually use a vintage pattern and often, old fabric.  These reputable seamstresses usually tag their clothing or make it known that they are reproduction clothes.  The fabric so often used in the fifties was semi-sheer nylon.  Often the nylon was flocked with a pattern such as flowers.  Organdy was popular also, though organdy can still be found in fabric stores.  Look at the lace also, cluny lace was used extensively which is a cotton lace (not frilly at all).  Ideal used attached muslin slips on their dolls and used this type of lace.  Toni dresses as well as Saucy Walker dresses will have this attached slip in muslin with cluny lace trim.  

It's not a daunting task to determine if a dress is factory, trust your eye, and use these simple guidelines.