[Eric]

Yes, it seems like an interstage transformer. The connection to the speaker is a bit strange, unless it is the common B+ supply to both the 226 audio stage and the 71A output.

What does pin 2 of the 71A connect to? The other terminal of the speaker seems like it should connect there somehow.

Pin 2 of the 71A goes to the speaker.
 the other side of the speaker goes to the interstage and the center coil in the picture. the other end of the interstage coil goes to the plate of the 226

would this work?   https://www.tubesandmore.com/products/P-T124D

I should have probably drew this and added from the get go.