I believe so. The 'X' on the back probably lines up 30° to the guide bar.
I asked about the file size, as the offset would be different for different diameter files. The Forester model (linked above) offers different sizes, while the Bailey's (aluminum?) only lists one size.
Try holding it up to a 3/8 chain, in the way you describe, and see how the file sits. Should be pretty close.
I don't know where you got the °, but I copied and pasted yours; sure beats my usual *.