I happen to own over 70 CAC gold stickered PCGS and NGC slabs at least 2/3 of which I submitted them myself over 12 years ago to CAC. I too have not sold any of them.
I understand your hesitation to sell them even to Seth who made a strong offer.
I happen to believe that these gold stickered slabs will continue to get stronger and stronger as CAC is ramping up their pricin and reducing future CAC sticker submissions. This will make gold stickered slabs only more rare in years to come. This is essentially sticker/slab collecting which is fairly new.
Remember, back in 2009 and 2010 I paid $8 each to have my slabs reviewed by CAC with a full credit on submissions that failed. Fortunately, very few failed.
If you keep your copper cent in an intercept box your red cent coin has a good chance of staying fully red. Adding a few cheap raw red copper cents from the 1960’s in your box will help keep your slabbed red cents red.