Broke the pivot shoe on RSVP vinyl tilt window balance assembly

I'm looking for a replacement shoe, shoe assembly, or possibly even a full replacement balance assemblies (I assume I'd need to replace as a set?).

Any chance you have a shoe assemply that will work, or even just the case metal part I broke?

There are three pics attached, as described here.

Front:
- As I face the window from inside the house, this is the balance assembly from the right side.
- Width is 1.25 as measured below
- The shoe appears to be removable out the back, IF I could get the gray tab to release.

Side.
- Spring has a number stamped on it - circled in red. Number is either a 6 or a 9.
- The spring is .5 wide

Back:
- back of the assembly.

Any assistance would be greatly appreciated.

Thanks in advance,
Ted

If not a perfect match, the 15-175 is pretty darn close. Am I correct in thinking that this part will work on either side (left or right), and if I've only broken the pivot shoe, I can order one of these, and move the current springs over to the new shoe, and re-install?
Ted

And... 7 years later, and I broke another one (since my initial question back in 2016!).

I see the 15-175 is discontinued. There is a reference to a 15-177.

Are they functional / size interchangeable? Anything I should check or watch out for?

Thanks in advance,

Ted