Holy Diver;
I do believe that RC is correct in his assessment of Leupold's ability to service your older Redfield, but check with them by all means. Just call 'em up & talk with them, they're very friendly folks. If, as both of us suspect, they can't really help you, I'd then try Premire Reticles.
However, until you know that there's something wrong with it, I'd leave it alone. There's no sense in trying to make it fail with some sort of torture test. As the year turns, just take it out of the house some cooler morning & see if it fogs. I've got a 1960's Denver Redfield that's still doing just fine after all these years.
900F