Robert, yes, "Night Sights" are included from the factory. The cost difference is due to mostly to stock level as Buds prices are tied directly to stock level.

yes the NS= night sights specs HK P30S V3 DA/SA TRIGGER 40S&W 3.85″ 3-DOT NS 3-13RD W/SAFE – HK 734003SLEA5
Manufacturer: HK
OTHER FEATURES:: AMBIDEXTROUS CONTROLS DUAL SLIDE RELEASES AMBIDEXTROUS MAG RELEASE V3 DA/SA TRIGGER REAR DECOCKING BUTTON
OTHER FEATURES2:: AMBIDEXTROUS SAFETY LEVER
CALIBER: .40SW
TYPE ACTION FUNCTION: SEMI-AUTO
GRIP MATERIAL: POLYMER
FINISH: COLORED
FRAME MATERIAL: POLYMER
BARREL LENGTH IN INCHES: 3.8500
MAGAZINE CAPACITY: 13.0000
NUMBER OF MAGAZINES INCLUDED: 3.0000
AMBIDEXTROUS SAFETY: Y
TYPE OF SIGHTS: NIGHT SIGHTS
WEIGHT IN OUNCES: 27.5200
Dimension: 3.40 X 9.15 X 11.15
Height: 3.4000
Width: 9.1500 buds prices are computer controlled and this is what Buds says about pricing Our website updates every 20 minutes, 24/7, with our current inventory and replacement cost. We do not price our guns manually based on our cost in each, rather we use a live download from manufacturers and distributors to set our price based on our current replacement cost. As our cost changes, the corresponding website price of each make/model will change up/down accordingly. Although our profit margin remains unchanged, our advertised prices will change frequently, sometimes several times per day.