Columbian Muestras Paraguay Scott 399-402. Did I Overpay?

I bought these mint blocks tonite and seller accepted my $40 offer was asking $60. Others are asking $250 for similar blocks and $40 for mint singles. I don't have foreign Scott catalogs wondering did I get a good deal, or overpaid? Also, are they valued in Scott similarly or is the 7 peso the key stamp?

Thanks for your thoughts.

http://www.ebay.com/itm/35067648960...69&ext=28294

Scott does not value specimen stamps, so one cannot tell what the value is from that catalog.

Typically specimen overprints are created in volumes unrelated to the face value, since they send the same number of each to UPU members. This means tat street values for them tend to be constant and don't reflect the scarcity of the postal version. This means that often high catalog stamps sell for much less with the overprint and low catalog value stamps sell for much more with the overprint. I don't know for Paraguay, but Argentina examples sell for $1-10 from that era.