One would think if you left existing seats in place, they would "Grand Father" over and be legal without. Being that I removed ALL the seats including the drivers seat, and replaced the drivers seat with a truck Air Ride, and installed another Air Ride for shotgun, I'm going aheand and putting in some lap belts.
I can get tan lap belts for $8 plus shipping HERE
Same guy has shoulder belts for $16 HERE
This particular ebay seller has some interesting stuff, including electric wiper motor & control unit, I'm looking at them to replace the air wipers I have now... Everything he's got is RV related...