With all the new inventory that just came out with the update it's really not anymore.
I have gotten quite a few of them with little problem. Its not like a rare set or a regional exclusive DLC. Those things are considered rare. Perhaps when the game first came out it might have been rare but its been 4 years since the game came out.
Later on today if you will be around I can give you a couple million free of charge. However if your looking for TBT bells can't really help you there and even if you do sell it the most TBT you get would get would be 2-5 TBT and possibly at the most maybe 25k if that.
Let me know if you will be interested and around later.