I have 4 Mullard EL34's that came out of one of my modified ST70's,
they are double getter, XF1 and XF2's. I have no way of testing for
matching puposes, but they held bias well installed in an amp with
individual bias pots. Printing is long gone, but some date codes are
visible as well as the XF1 and XF2 markings.

Would like to trade for a good-matched pair of RCA 6SN7/5692 Red Base
tubes.

I have decent feedback on Ebay, Audiogon, and Head-Fi.org

If interested, let me know, pics can be sent.

Tom
Portland, Or.