Fnv1a hashing of C# Guid

Question

I have the following implementation of the Fnv1a hashing for a string, which should be correct:

public static uint Fnv1a(string toHash, bool separateUpperByte = false)
{
    IEnumerable<byte> bytesToHash;

    if (separateUpperByte)
    {
        bytesToHash = toHash.ToCharArray().Select(c => new[] { (byte)((c - (byte)c) >> 8), (byte)c }).SelectMany(c => c);
    }
    else
    {
        bytesToHash = toHash.ToCharArray().Select(Convert.ToByte);
    }

    uint hash = FnvConstants.FnvOffset32;
    foreach (var chunk in bytesToHash)
    {
        hash ^= chunk;
        hash *= FnvConstants.FnvPrime32;
    }

    return hash;
}

I now want to hash Guids instead of strings. Will the following give a good fnv1 hash?

public static uint Fnv1a(Guid toHash, bool separateUpperByte = false)
{
    IEnumerable<byte> bytesToHash;
    if (separateUpperByte)
    {
        bytesToHash = toHash.ToByteArray().Select(c => new[] { (byte)((c - (byte)c) >> 8), (byte)c }).SelectMany(c => c);
    }
    else
    {
        bytesToHash = toHash.ToByteArray();
    }
    uint hash = FnvConstants.FnvOffset32;
    foreach (var chunk in bytesToHash)
    {
        hash ^= chunk;
        hash *= FnvConstants.FnvPrime32;
    }
    return hash;
}

We use the hash for determining partitions in a Service Fabric cluster. My concern is whether this implementation distributes the keys evenly.