In general, no. I don't think this helps others find the question, nor is it very useful when you stumble upon the question. In some exceptional cases a date may be helpful, for example when it's a much publicized deadline (e.g. the 29th of March 2019, at one point Brexit deadline or December 2019 election to refer to the upcoming UK election). If we do include those, it's probably best to write the month in words to avoid confusion (see this question on Skeptics Meta).
Bonus: how to search by date
Quoting from the help center
You can use specific dates or date ranges to narrow results down to posts created or active within a certain time period, using the following operators:
created: to specify when the posts were created
lastactive: for posts active in a specified time period
Dates can be entered in the following formats:
- year only – e.g.,
created:2012..2013 searches posts created from January 1, 2012 through December 31, 2013;
created:2012 searches posts created from January 1, 2012 through December 31, 2012.
- year and month – e.g., created:2012-04..2012-05 searches posts created between April 1, 2012 and May 31, 2012.
- day, month, and year – e.g.,
lastactive:2012-04-03 searches posts who were last active between 12:00 AM on April 3, 2012 and 11:59 PM on April 3, 2012.
1d are shorthand for "last year", "last month", and "yesterday" - e.g., if today is April 15,
created:1m searches posts created between March 1 and March 31. (You can substitute any number for
1 to look back that many years, months, or days.)
Relative dates in a range (
1y..) look back to the same date in the previous period - e.g., if you want to see all the posts active in the last three months, use
lastactive:3m.. On April 15, that will show posts from January 15 up to the most recently active. You can close the range as well:
Please note that all times are recorded in UTC; the results may not match your timezone.