The tube on the right is dated 1958. The "188-5" legend next to the 4-digit date code was for the GE tube factory in Owensboro, KY. The Tung-Sol branded tube appears to have been made in the RCA factory. The octagonal "stop sign" outline around the type number was how that factory printed the indelible type number on the glass.
The pictures make it appear you have replaced every, last electrolytic capacitor. Bravo! Way too often I hear "replaced the caps", but when you look inside only the big ones are new, and all the small ones are still original.
Keep us informed how it turns out.
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