private DateTime RetrieveLinkerTimestamp()
{
    string filePath = System.Reflection.Assembly.GetCallingAssembly().Location;
    const int c_PeHeaderOffset = 60;
    const int c_LinkerTimestampOffset = 8;
    byte[] b = new byte[2048];
    System.IO.Stream s = null;

    try
    {
        s = new System.IO.FileStream(filePath, System.IO.FileMode.Open, System.IO.FileAccess.Read);
        s.Read(b, 0, 2048);
    }
    finally
    {
        if (s != null)
        {
            s.Close();
        }
    }

    int i = System.BitConverter.ToInt32(b, c_PeHeaderOffset);
    int secondsSince1970 = System.BitConverter.ToInt32(b, i + c_LinkerTimestampOffset);
    DateTime dt = new DateTime(1970, 1, 1, 0, 0, 0);
    dt = dt.AddSeconds(secondsSince1970);
    dt = dt.AddHours(TimeZone.CurrentTimeZone.GetUtcOffset(dt).Hours);
    return dt;
}

Datestamp of compile time

Embed compile time in executable

C#