It is hard to find high case colors condition pre-WWI Belgian tradename doubles. This is a c. 1900 Union Machine Co. by Simones, Janssen & Dumoulin.
SJ&D also tradenamed Prize Machine Gun, The Interchangable, The International, The Continental (carried by Granny on the Beverly Hillbillies), W.H. Hamilton, H.S. Brown,; often marked with the June 20, 1883 T.J. Bovy patent.
I suspect most tradename guns had case colors similar to that of U.S. makers
Pre-WW1 Francotte VL&D 14E 20g
This is a very nice 1942 Deforney Super Saive 20g
We've got a good collection of U.S. maker's colors, but I couldn't find a high condition Lefever
. Could someone please post an image?