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Although a lot of the specs for those assume use in reverse leakage mode, they do give an open-circuit voltage figure, which shows they can be used in "photocell" mode which appears to be what that circuit may need.
They are cheap enough to have a go, anyway.
My only other thought is that if they are for the arm tracking system rather than one of the general detectors, replace both with the identical part to maintain the "balance" of the servo system.