'63 K10 - Need help finding drum brake backing plate

[gtyap]

I need help badly finding a front drivers-side drum brake backing plate for my 1963 Chevrolet Suburban K10 Carryall.

I understand the front axle that year on the K10 trucks/Suburbans was not made by GM, but by DANA Spicer >> Dana 44.
The number on the backing plates are 310299-L and 310299-R

My understanding is that it was also put on these vehicles:
Dana Spicer 44 Front, Beam & TTB
Chevrolet:
1960-1976 K5, K10, K20
Ford:
1959-1979 F-100, F150, F250 4x4
GMC:
1960-1966 1000, 1500 series
International Harvester:
1953-1968 R-Line, S-Line, A-Line, B-Line, C-Line 4x4 trucks ½ - ¾ ton range
Jeep:
1957-1965 FC-150
1957-1965 FC-170
1963-1987 J-Series trucks (exc. Some 1 tons)

I've checked all the vintage vehicle parts, called dozens of salvage yards, and put requests out on salvage yard part aggregator websites... no luck.

Anyone have any suggestions??

Here's the thread on what I've done on the Suburban and it includes a link to all pictures, including the brakes: https://www.67-72chevytrucks.com/vbo...d.php?t=860378

I'd be grateful for any help!