Can someone help me to find out more information about this watch? It was stored by decades in my family member's house and now nobody knows what it is apart from the company name.

Can someone help me to find out more information about this watch? It was stored by decades in my family member's house and now nobody knows what it is apart from the company name.

If it was stored for decades in the house, when did it acquire the new strap??
It could be a Cal 83 which was made from 1930 to 1947, or a Cal 88 made 1946 to 1964. We need more info to be certain.
It's a very nice IWC.
Nothing to add apart from suggesting you ask a watchmaker to pop the back off.
Check the movement number and case number (inside the case back) and post them here.