MIT PGP - PGP UI - VIACRYPT mime

[Gary Jeffers]

Cypherpunks,
   Question concerning MIT PGP 6.2 & PGP 6.2 ui. If it is known that
the PGP that encrypted a msg is one of these two versions, then can
it be determined which of these two versions did the encrypting?
Also, can it be determined that it was not VIACRYPT that did it.
Note: If it can be determined that PGP 6.2 ui did it, then it might
be a neat trick to change the ui version to mimic either of the
other two at user command.
                                                    Yours Truly,
                                                    Gary Jeffers