Do we have stable versions of Staged_ledger_hash and Ledger_hash; do we really need the asserted?

Yes, because Staged_ledger_hash.t and Ledger_hash.t are derived from Pedersen_lib.Pedersen, which is not versioned as of right now.

I think you can use Pedersen.Digest.Stable.V1.t here, and remove the asserted.

Pedersen.Digest is not stable yet.

and then also use Pedersen.Digest.Stable.V1.t here

can you write just module V1 = V1_make.Stable.V1 ?

Make is asking for a bin_io module, and the choice of that input gives new a particular version.

So I would write something like:

module Input_32 = struct
  module Stable = struct
    module V1 = struct
      module T = struct
        type t = ...Int32.t   bin_io, version {asserted}
      end
       include T
   end
end

where each version is a choice of the input to Make. And then something like:

module Nat32_make = struct
  module Stable = struct
    module V1 = Make (Input_32.Stable.V1)
  end
end

where that choice is reflected as a version in Nat32_make. So a client of Nat32_make that wants a versioned type would write something like Nat32_make.Stable.V1.Stable.V1.t.

this part looks good

see comment above .... I think this should just be Input_32, which can contain all possible versions.

I think this can be omitted, since you'll always pass a particular version to Make, rather than the whole module.