US 1615cd Break In Precancel Lines

Is there anything particularly collectible about the examples shown below -- namely the second pair where there is a break in the precancel lines that are not present in the first pair? (Both are dull gum varieties.)

The precancel line gap is relatively common for that specific issue. On stamps printed by the Cottrell Press before BEP began adding plate numbers, the gap appears every 12 stamps. The gap is normally collected as a pair.

Later on when plate numbers were added to the coils, the plate number was on the stamp to the left of the joint line. Interest gained in collecting the precancel line gaps based on position relative to the joint line. The notation is based on stamp position to the left or right or on the joint line: ...2L, 1L, line gap, 1R, 2R...

Line gap positions greater than 2L or 1R necessitates a coil strip larger than the conventional strip of 5.

For coil stamps with plate number but not printed on the Cottrell Press (i.e., no joint line), the same notation is used based on an imaginary joint line through the perforations immediately to the right of the plate number stamp.

I should add, that for those who like to look at tagging, there are also gaps in the tagging. This applies not only to overall tagged stamps, but also to block tagged stamps where you will see a small sudden vertical shift in the tagging blocks representing the edge of the tagging mat. Of course, you will not see them on stamp with pre-phosphored paper.

Here is a link illustrating what I was trying to describe:

http://www.pnc3.us/pnc3.org/Wash-2006/Page%206.pdf