National HRO questions

[Stephens, Al]

Gang,

     Working on a pretty decent HRO-50T (and was surprised when listening to
SSB on 10 meters, no added product detector, and finding it very nice copy -
and rock stable!  Pleasantly surprised, that is) and have a couple
questions:

     1.  Is the AC coil (15 meter bandspread) interchangeable between the
HRO-50 and the HRO-60, or is there a different one designated for each
receiver?  If so, what is difference in designation?

     2.  Does the XCU-300 crystal calibrator (for the NC-300) work as-is in
the HRO-50 (I don't think so right off hand - looks like it won't physically
fit).

     3.  Is the designation for the crystal calibrator for the HRO-50 the
XCU-50?

     Thanks in advance  (and I did use the HRO-50 in last CX).

     73,  Al  N5AIT