You can use the RN# right there on the tag as a starting point.
Use this formula (it's not perfect, but it's pretty darn good):
x-13,670=
y/2635 = z
z + 1959 =
most recent any item with that particular label can be (not its age, but it's oldest possible age)
KEY:
where x = your RN# (in this case 22347)
13670 = the first RN# ever issued
2,635 = the approximate quantity of RN#'s issued each year
1959 = the year the first RN# was issued
So...
22347-13670 = 8677
8677 divided by 2,635 = 3.29
3.29 + 1959 = ~1962/63 --> the very oldest anything with that label can be
If you're stumped, it's a good starting point.
Beware WPN #s which were sometimes converted to RN #s, they give kooky results.
The formula doesn't work with WPN #s.
So even without seeing the item, I could tell you it can't be older than early 60s. But looking at the color, the shape, the fabric, the styling, tells you it's late 60s.
If the content is printed only on the hangtag, and not on a permanently attached label, and there are also no cleaning instructions on a permanent tag, you know it's from before the mid-70s. Another clue.