No. There are partial answers based on examining $0 and $ENV{PATH}, with algorithms rolled up into File::FindBin, but nothing will ever be completely unspoofable or accurate.
Comment on Re: How do I find what dir the perl script is running from?
Update: Just FYI, I interpret the original question
as wanting to know about getcwd() and use Cwd,
rather than wanting the full path to the script (which is
what File::FindBin tries to find in a very perverse way).
But it is hard to say for sure.