As a rotary, it does indeed take a 15x1 needle. It is regardeless of the age. I don't believe the rotary ever took different needle.

If you got the machine, here's a link to a manual: www.ismacs.net/white/manuals/white-rotary.pdf

I have a 1917 White FR rotary treadle. I really like using it, its my daily use machine. The hand wheel turns away from you, it uses a modern 15x1 needle. Make sure it has the bobbin case as they are very hard to find. Threading is easy once you get used to it. The bobbin case threading is different from any machine I've ever used.
Sharon in Texas

I found this to be true when I first got my machine. I cleaned and oiled it as it was very very dry after non use and took the bobbin race off and got it back on wrong, took a while and two people to figure out what was wrong, of course one person (me) was working with 1/2 a brain;).

White FR info needed
 

Hello. I have a 1917 White Rotary FR. I'm looking full assembly instructions. I have the user manual but it is not extensive enough. I know that info is scarce. Any ideas?