MSMPI v1 symbols are available!
The symbols for MSMPI v1 RTM and SP1 are available on the Microsoft public symbols server @ https://msdl.microsoft.com/download/symbols.
You can access the symbols from the debugger (and other tools) using the symbols server symbols path
e.g., srv*download_cache_folder*https://msdl.microsoft.com/download/symbols
Enjoy
.Erez