The short answer: yes! In fact you can find and read the real trademark by searching HERE for Serial Number 73150505.
If you check out the above link and scroll to the bottom you will see that the trademark is listed as "LIVE", that means it is still valid and in force.
This was filed all the way back in 1977. At some point I'd like to talk to some folks from the industry that were around back then to better understand why Gibson/others didn't fight this trademark, but for now I will summarize the best arguments I've read on the internet (know that this may not be true). Essentially the argument goes like this: Nobody other than DiMarzio was selling an all-cream pickup without a pickup cover at the time. While Gibson had shipped guitars with zebra and double cream (or "double white") pickups as early as 1959, these pickups were always shipped with a cover soldered on, which sometimes would be loosened during use or sometimes would be purposefully removed by the player for a slightly hotter output and high-end response. So while early examples of famous players using double cream pickups exist (see Clapton playing his Les Paul from his John Mayall days below), they couldn't claim the trademark because that "prior use" was essentially an altered product. That makes sense to me, but whether or not it is historically accurate or would hold legal water I'll have to dive into later.
If a double-cream pickup is something you must have, and you are unwilling to alter a pickup yourself or have one modified, the below vendors sell them (starter list - let me know if I'm missing any!).
- DiMarzio (of course!)
- Carvin sells their pickups in all cream
- Bare Knuckle