Fulton's are adjustable. That includes the vehicle width. The main differences in the different models of Fulton visors are the end mounting brackets and whether a center support is needed. There is some wiggle room in the end brackets though so even if you can't find the correct brackets for your '41 you can still make them work. The correct bracket for your '41 will likely be where the top leg is closer to mid bracket than toward the end. That is the correct bracket for my '38 and we were able to make the later model brackets work fine with a little 'massaging'.
You may find some help here. The brackets you need to look for are pictured in Step 3 and Step 9A. The most common brackets and the type we made work on my '38 are pictured in Step 9C where the upper leg is almost to the end of the bracket. You need to make sure you have a two or three inch opening along the back of the visor to let the air pass through. If you don't your visor won't last long if you get much over 30 MPH.
