the proper pinout for a 2SC1971 is BEC, but there are counterfeits out there 
because this device has long been discontinued.... 

the only proper way to test the device is to test it with a beta tester, 
and make sure it has somewhere near the expected Hfe when connected properly... 

the counterfeits have C as the center pin and heat sink tab, and will not 
provide any gain with C and E reversed on the tester. the purpose for using the
enter tab as E is quite simple. the heat sink tab makes for a rather large 
stray capacitance. if this stray capacitance were in the collector circuit, it 
would make the proper design of an RF amp very difficult. using E as the tab 
simplifies things, since in most RF amps E is always grounded, and the stray 
capacitance between the tab and heatsink doesn't matter.