Here are four beautiful 1965 tubes of identical construction, three of them are labeled Tung Sol and one is labeled RCA. They are matched within eight (8) milliamps with getters flashing intact, no shorts, no gas and good life test. Where JAN MIN is 5,000, the test results marked in white on the tubes are:
1. 8,000 \ 92ma. Tung Sol, date code 3226507-3
2. 8,100 \ 95ma. Tung Sol, date code 3226507-3
3. 8,100 \ 95ma. Tung Sol, date code 3226507-3
4. 9,000 \ 100ma. RCA 7335
Some years ago, I bought these tubes for investment from a vintage tube seller who made the white markings. I'm baffled as to why he marked them, but it doesn't affect performance. Price is $960 for matched quad.