Can't speak specifically to your question, but when I transplanted a 617 diesel into my 107, the tach wouldnt work - diesels use a VR pickup for a signal while gassers use an ignition signal. Even though the actual modules are different, they screwed right in without modification. Now the sweep of the tach face was also different (gassers rev higher) and that wouldn't swap right in but with just a bit of trimming I was able to epoxy the diesel tach face over the original one and since the bezel covers the outer edges of the face, there is no visual clue that anything is different.
So I would check the sweep of the other speedometer face and if it's the same you might be able to use my trick to get the job done.
There used to be someone that produced new faces for gauges. They were printed on vinyl and would stick over the face...mostly to emulate AMG faces or change to black on white scheme. If you're handy with photoshop and could source the proper substrate that might be a solution too.