Woldan
nice 602 that you've picked up - perhaps you might be able to source an old peep our your way, but they are as rare as hens teeth here in Oz.
Hopefully someone may be able chime in with drawings to make one - but it will take a lot to do so as they are pretty intricate.

Bolt strip - video down a bit
https://www.thestalkingdirectory.co.uk/threads/brno-zkk-bolt-disassembly.37115/

Exploded parts list - not the peep one unfortunately!
http://nitroexpress.info/ezine/TechFiles/Brno-ZKK-602-Exploded-View-Parts-List-A4.pdf

NE previous posts about ZKK peeps
http://forums.nitroexpress.com/showflat....e=0&fpart=1
http://forums.nitroexpress.com/showflat.php?Number=169817

Hope this helps
93x64mm