Another nice pair of:

2 NOS Siemens Tubes CCa = E88CC 69228  

Factory code inside : "A4 9B + A4 9H "

Good tube starts with gm 8.5mA/V

Test result S - gm test : 

10,0 + 9,5 mA/V and 9,6 + 11,0 mA/V

with Burn-In in special device