Does anyone really know what day it is?

Grates on an unpaved road, Metro Vancouver, BC

These metal grates are on a steep, unpaved road near where I live. The grates are over a concrete channel that acts as a conduit for water, preventing the sometimes torrential rainfall from washing out the road.

I presume that the numbers are a production date. But what is the date?

• December 6, 2003?
• March 12, 2006?
• December 3, 2006?

Based on the numbers on the grate at the bottom of the photo I presume that the format is Month Day Year, so March 12, 2006. But given that all of the numbers on these two grates are 12 or under, there is no sure way of telling.

If this date is intended to be some form of production tracking or quality control system, it is a bit confusing and does not seem to really do the job. At least to my untrained eyes..