The Renton website used to say that a CPL was required for non LEO to carry a firearm in city parks:
"Section 3. Weapons & Fireworks
It is unlawful for any person except duly authorized law enforcement personnel to possess any firearm, fireworks, firecracker, torpedo, explosive, air gun, sword, knife, bows and arrows, BB gun or slingshot without the appropriate concealed weapon permit in any park until a written permit has been obtained from the Park Board."
I emailed the Webmaster, Police Chief, and Mayor on Sunday (the 8th) with the actual city ordinance 4419, which only limits park firearms possession that is not "otherwise permitted by law":
"Section 3. Weapons & Fireworks
Except as otherwise permitted by law, it is unlawful for a person to possess in any park, any fireworks, firecracker, torpedo, explosive, air gun, sword, knife, bow and arrow(s), BB gun, paint ball gun, or slingshot. It is unlawful for any person to possess firearms in any park except as otherwise permitted by law." -
I was surprised when I found that the website had already been updated today. The original page for the Park Code which was incorrect has been replaced with a link to the actual city code above.

Here is the page that now references the PDF (click on Park Rules and Regulations):

The original page with the incorrect code can be found here:

Hopefully this helps prevent a little misinformation. I know that I myself, was originally under the impression that park firearms possession without a CPL was illegal per Renton City code as displayed on the .gov website until I decided to dig deeper.