I have a few old 23 channel CB's--no Cobra's but some others like Roberts and Pace,Realistic,etc...some others I have are so old they used crystals and only had a few channels..
Supposedly the 23 channel ones were a "full" 5 watts output,while the early 40 channel CB's were actually 4 watts ,despite being rated at 5 ..how true that is I don't know...
I'd bet most of my old CB's long stashed away in my garage might not work ,or work well,after sitting so long--capacitors and other components often degrade over time..but on the other hand "they dont make 'em like they used too" may apply here too...if they were not subjected to a lot of moisture or high temperatures they might be in good shape still...
I tired firing up my Courier Centurion SSB base station in my room the other night when I was bored--it still works,but sitting took a toll on it--the power mike battery died and corroded the battery holder,the talk/receive relay sticks when you key it up,and the power on switch had to be flicked several times for it to power up--also the volume control is extremely "scratchy" now...it'll need some re-hab for it to be a good unit again now..so even indoor "dry" storage can cause problems..