First Class Flag And Liberty - Distinguishing 3966 And 3972

Can someone explain the difference between 3996 and 3972 for me?

According to my Scott 2010 Specialized, both are self-adhesive, 11.25 x 10.75, serpentine die cut, and both were issued in booklet panes of 20. Both have the features (microprinting etc.) that distinguish them from 3974.

So what am I missing?

3966 was issued both in a booklet pane 20 and a regular pane of 20. It is listed as 11.25 x 10.75, with no mention of differing numbers of die cut sides (unlike 3974, which was only issued in booklets and always has either 2 or 3 die cut sides).

OK, sooo, perhaps the difference is in this number of die cut sides? Did 3966 always have FOUR die cut sides, even from the booklet?

In that case, would the distinction be: 4 sides = must be 3966; 2 or 3 sides = must be 3972.

Or am I missing something else here?

PS If the sides are in fact the distinction, then does this always hold true wherever a stamp is listed in Scott as both Pane of 20 and Booklet Pane of 20 with no mention of differing numbers of sides being perf/serp dc? -- i.e. does being issued in a regular pane, as well as a booklet pane, always indicate that there are 4 perforated/sd cut sides on every stamp no matter which type of pane it's from? [[If so, this would help me a lot , but I don't want to jump to conclusions.]]

Hope this isn't too convoluted.

Thanks.
Jan

This link may help you some:

http://www.ourstampsnstuff.com/liberty.htm

The simplest explanation suggests that 3966 does NOT "glow" but has microprinting; 3972 "glows" but has NO microprinting.

Fuzzy blow up of the 3966 microprinting

Thanks, guys. I misread my Scott -- I thought it said 3972 had the microprinting. But I just reread and it says "without".

The website is great, though -- thanks again wt1.