I ran into something similar on my 59 370 LCF GMC. When I bought it, all the springs on the rear were broken up and laying down in the drum. Mine look to be the same as yours. I ordered the correct springs from Rockauto. The shoes looked new and were the right width and fit, with about 1/2 inch of shoe left. So I was not going to buy new shoes. But I did not know why ALL the springs were broken.
I did find out the shoes had a tab, but no holes for my new springs. The tabs were nowhere near the right location. (Someone had put the wrong shoes on it.)
SO, with some careful measuring, I drilled holes in the shoes and they work perfect now.

57 GMC LCF 370
55 John Deere 40-W
59 John Deere 430-W
2000 GMC 4x4
56 John Deere 420-W
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