Glossybox posted their black friday discount code in the comment section on their last facebook post:
"GlossyBox.com For those that didn't receive the email - Black Friday Deal: Get 40% off + Free Shipping (40% off first month subscription to GLOSSYBOX). Enter code - Black40. Ends 11/25."
This code probably is an auto-renew sub with discount on Dec box, whereas the TG40 code is just the Dec box and if you want more boxes you'll have to sub again.
I just checked and I got the monthly subscription with the TG40 code I used yesterday! I'm glad they extended the offer with a new code. It's such a great deal!