There's a margin of forgiveness involved with bolt on hubs, as your IGH is.
Measure the dropout width (separation) and compare to the hub. if the locknut width of the hub is smaller, you can add spacers, but figure that the axle's overall length has to be about 35mm longer than the dropout separation (minimum).
That's 15mm for the two dropout thicknesses, and 10mm per side for thread engagement of the nut. If you're close, there may be some fudge room, but not much.
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.