Hi everyone, I am new to stamp collecting and my Knowledge is limited but I can usually find out the information I need through google but this one block of stamps has me stumped.
A correos Espana Stamp with VIVA FRANCO printed on it. This is an example of what stamp I am on about.

I have a block of four of these which have no perforation and still in Mint condition with a light hinge.
Why wouldn't these have been perforated and is this something which would increase the value ? If any one could help me out it would be fantastic, I will also post a scan of the stamp block tomorrow.
Cheers