Yes, you're mistaken. There was an aftermarket quilted felt silencer pad available that laid on top of the rocker arms for people who didn't know how to adjust valves properly, but the valve cover with the vent slots didn't have any kind of filter inside the cover. It was just open slots that funneled rain water from the cowl vent into the head and down to the crankcase pretty effectively.

What are you planning to do with that "seized" engine, and where are you in Tennessee? I collect stovebolt engines, regardless of condition. Most of them are fixable with a little work, or at least good for parts.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!