There are two patterns of cap worn in WWII. The issue and PX styles. The issue cap is, what it says- this was the cap issued to all troops by the Quartermaster of the US Army. It has a pleated top, and is similar in profile to the cap worn in WWI. The top curves upward from the rear and slopes downward toward the front. The PX caps were purchased privately by soldiers- they were sold in the PX's, department stores and tailor shops around country. They are basically rectangular and do not have the pleat in the top. This is the cap often erroneously called the "airborne" model by living historians who study history via mini-series and action figures. Both types were widely worn and both are equally correct. Most reenactors prefer the PX style due to it's "sharper" appearance and fetish with anything rumored to involve paratroopers.
Branch of Service Piping
Soldiers wore colored trim (piping) on their garrison caps to show what branch they were (infantry, artillery, armor, etc). We stock all caps with blue (infantry) piping since this is what 95% of reenactors portray. (This includes airborne infantry). We have other colors and can sew them on for a $14.99 fee. We must partially disassemble the cap to do so and it takes about 30 minutes. This is the reason for the fee. It will also delay shipment 3-5 days depending on our sewing schedule. Thanks for understanding. See below for caps with custom (other than blue) piping.