BiltBest Truth old Casement Windows

I have two windows that are missing the stem, the cover, and the handle. I read a post from someone to Swisco that I may need to replace the EntryGard Dual Arm Operator, 39-031 and 39-032. I looked at it online and it shows that the long arm is 10 3/4" but mine is only approximately 9 1/2". The short arm is the same at 4 7/16". Can you please tell me the part number so I can order the correct one. The pictures above show two different windows that have the same size operator.
Thank you.