one of my favorite source books for background, label, dating and other information for aloha shirts is "The Aloha Shirt" by Hope/Tozian.
Condition plays a huge role in the value of them, "silkies" are considered the most desirable, however the tapa-cloth-inspired prints of the 60s have their own collectors gaining in popularity: by far, though, the old rayons are most highly sought after.
There were many highly skilled aloha shirt manufacturers; some of them were little mom and pop places that simply used a Made in Hawaii tag, so it really depends on the print, the CONDITION and the size (the bigger, the better, generally)