There are several other NBC feeds that weren't listed on the 4DTV channel listings
B4-1: NBC (Occasional) which was occasionally lit up
B4-10: NBC (Occasional) which was active around 3:45PM Eastern central time
(Though SBS4 had 10 transponders, there was more beyond that)
B4-12: NBC (Occasional) which was the newsroom full of terminals and monitors
B4-19: NBC (Occasional) which had the NBC BURBANK Bars and Test Pattern
K2-15 (Ku generic KC on 4DTV) in 1998 had a GE Americom slate and a 24-hour chyron (Though there was still NBC traffic on K2 back then, Conus Communcations shared a satellite on there as well (as did ABC))
My Orbit Magazine (June 1998) and several rec.video.satellite.tvro threads list SBS4 (77 W) as an inclined bird (alongside GStar 3), Satcom K2 (81 W) wasn't in there (but it was also inclined as well).
Though there were plenty of NBC affiliate and news feeds on SBS4 back then (KTTC Rochester, MN, KWES Odessa-Midland, KCBD Lubbock, WLUC Marquette, WGBC Merdian, MS, KTVZ Bend, KJAC Pt. Arthur/Beaumont (News 4 Texas), WBOY Clarksburg, WV, WTVA Tupelo, WVVA Bluefield, KTVF Fairbanks), although NBC used it as private feeds for their affiliates. Much like the other networks, NBC requires all of their affiliates to have newscasts but there were several other NBC affiliates that didn't have news outlets at the time (including WMGT Macon, KTGF Great Falls (Fox secondary), KVEO Brownsville, KPOM/KFAA Fayetteville, AR (which relaunched a news division in 1999) and WLTZ NBC38 Columbus, GA).