That's also idiotic because we don't put a leading zero in front of 1, 2 or 3 digit years, and neither will future historians put one in front of 4-digit ones - it's just gratuitously annoying.
Charlemagne was crowned in 800 AD, not in 0800 or 00800.
Pompeii was destroyed by the Vesuvius in 79 AD, not 079 or 0079 or 00079.
The battle of the Teutoburg Forest was in 9 AD, not 09, 009, 0009 or 00009.
Also why stop at 5 digits while you're being ridiculous?