Yeah that's right, initially the 1.8T was available in Sport and Cupra with the Cupra just having more toys (full leather, elec seats, auto lights and wipers). This didn't last long and both cars were replaced with one model called the cupra with the old Sports spec and the leather etc as an option.
Don't think the 1.6 was ever offcially available as a Sport (ie on the V5) but some people may sell their car as a "sport" when they have added bigger alloys etc to their 1.6 S or SE.
The 1.8T sport wasnt on sale for long so only a few about on W or X reg and maybe a few in 2001 but probably not. All the rest are called Cupra up until around 2004 or later when the FR came in.
Confusing I know!