"I suspect that the 40 watts/ch. is an IHF Music power rating. Everyting I have found seems to indicate that RMS output for 7189-a's in push pull would be in the area of 25 watts +/-. Still damned beefy enough for a tube amp of that vintage."
Yep your right about the power spec. Although not every source
I looked listed both ratings.
"I think I'll try bringing up gently this weekend ( I'll rig up a poor boy variac and give her a listen and see if it is in working condition)."
Yes you will need to be careful, It would really suck to end up
popping a major component because you got in a hurry.
Let us know how it all goes.