You may not be able to post in the JY but you should be able to browse and use the search function and see if anyone was/is selling any. I would start your search there.
Sometimes items are posted in the JY but not bought and still available. You can't start a WTB yet but you can look to see if any are there and contact those members.
RPF'er Russrepp makes some, you might search his Threads and see if he has any.
Also, you can buy similar new transistors at most electronics parts stores and with some work attach threaded post to the back that will work.