No. I was curious and checked - this: https://github.com/waylan/Python-Markdown is slightly below 3k loc mark (2977) excluding extensions, and by the look of it it's much more heavily commented (I didn't strip blank lines or comments at all). Markdown.pl has 1450 loc.
So - no, bullshit, you need to multiply by 2 at most in case of Python :)
Another interesting comparison would be with the Text::Markdown CPAN module which is Gruber's original code & comments converted to an OO interface with POD documentation added + bug fixes.
This comes (including blank lines, comments & POD) to 1739 loc - https://metacpan.org/source/BOBTFISH/Text-Markdown-1.000031/...
Perl makes it look small, if you have to write something like this in Java or Python, multiply the LOC by at least 20. But I assure it will be higher.