Park Ridge IL Precancel

Can someone shed some light on these as far as value and rarity ?
I found this article regarding them.

The coil issue from Park Ridge, Illinois has a very interesting history
and is a very hard issue to find both as a single and also a pairs. The Park
Ridge Post Office was robbed. The thieves took only uncancelled stamps
but broke the precancel coil rolls open and threw them all over the post
office. The remainder of the coils, 172 rolls of 500, was returned to Washington
for credit in 1935. Only 200 rolls had been used since 1932. Hence,
this issue became much scarcer and hard to find.

Scarcer than some, the bureau printed coil SC597, has a PSS catalog value of 2.50 USD.
'hard to find' is of course a relative assessment, but in fact they are easily available.

That is not the news I was looking for. As of now I don't actively collect pre cancels but I have a chance at a pair of the Park Ridge precancles and they appeal to me for 2 reasons. #1 is I grew up in the part of Chicago which borders Park Ridge so I know the area well, #2 is the article in which I copied the above statement, the rest of the article is here.

http://www.precancels.com/wordpress...ecancels.pdf