Hi Clare - The usual handset for the "Old Family" PRC-47 is the H-33 which has a carbon mic element. I believe the H-189/250's that are often used with the New Family gear like the PRC-25/77 uses a dynamic mic element and therefore not directly compatible with the Old Family equipment. And different connectors of course. (U-77 versus U-229). Also I don't think I have ever seen an H-250 handset with a volume control. (But I never say never! haha)
Have fun with the PRC-47. When they work, they work great...
Cheers, Tim
N6CC