Men say cam caps are bored with each head, thus each is unique, not interchangeable.
If so, whatever cam cap you might find as a replacement wouldn't fit the shaft properly, barring unlikely coincidence.
Could a machinist fit a cap to a head? Doubt it; centering the circle with the existing head camshaft centerline would be a challenge, seems to me; re-boring would produce oversize/oval profile.
Hog out camshaft channel for replacement bearing halves? Replacement of complete head likely less costly.
My understanding only; corrections an clarifications welcomed.