I am going to pop this over to the Nirvana forum for you
As others have said, it was one of those pony urban legends.
When a lot of ponies were first being discovered or remembered or discussed...there was always speculation about their source. I believe Jenny was one of those girls. When she first popped up, the most clear thing was her apparent similarity to TJ (simply due to colouring), therefore the speculation was that she must be something to do with TJ. With time (and the appearance of a backcard) it was quickly realised she was one of those lovely "variations" of a normal release pony.
However, all that being said, for all we know the colouring was deliberate
She is a very unique release so its perfectly possible. But only in the palette choice of a designer of course - so an homage rather than something deliberate.