HLV-H tailstock questions

My slowest-ever HLV-H renovation has reached the point where I can at least make parts from a chuck:

Now it would be nice to have a tailstock. Here is a front view of my tailstock casting,
with the four holes for the gib screws along the bottom:

I think this looks normal.

Here is the rear view:

The outer two holes along the bottom had brass-tipped set screws that pressed against the back side
of the dovetail. Is that a shop mod of the original design? I don't see these set screws in the drawings.

Here is a picture of the tailstock gib:

It is crudely made with saw cuts at the ends and the four tapped holes are not aligned. I am guessing this is a replacement for the original gib. Dimensions are 8.5" x 0.843" x 0.431" plus a 4 mill shim behind it. The gib is badly bowed. If I press one end down on a flat surface the other end pops up about 25 mills. I think it would only make contact with the bed at one point if I were to use it, and maybe that is the reason the previous owners added those set screws. Maybe it was bowed on purpose so it would act like a leaf spring, and the two set screws would allow a little adjustment of the back-to-front position of the tailstock.

I think I will have to make or buy a new tailstock gib, but I don't have the original part. Could anyone tell me what material it should be made from? Is it just a rectangular bar or does it have other features?

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