Yes, they are from different offers.
So-Soft Satin 'n Lace was the first version offered. There was no groom pony at the time. IIRC her brochure offered her, Baby Lucky (her cousin), the Pretty Parlor (but without Peachy), the Collector ponies, and the Birthflower ponies. So-Soft Satin 'n Lace was advertised as being "a soft lavender", but I've heard that she is actually magenta under her flocking.
I'm not sure where the magenta NSS version comes into play, but my guess would be she was a transition between the So-Soft and the later NSS lavender version.