I have an old Schneider (not for sale) that has 25mm thread. It has to have an adapter that has a 25mm inner thread and 39mm outer thread. Not a big deal but if you are looking at something like this, you would want to be aware and purchase an appropriate adapter or a lensboard.
As to f/ stop illuminations, I usually feel the click and count from the widest stop. Not a big deal if it doesn't have one. (many older but otherwise just fine lenses do not have illuminations)