Just booked hilux 3.0 vnt (loan not yet approved) & now umw introduced 2.5 vnt. Should i cancel the booking & apply for 2.5 vnt?

Been using my hilux 3.0 vnt for 3 months plus...generally satisfied with the performance
The car is only for family use & when i have fishing trip
Modification: only replace rear leaf spring shackle to reduce bumpiness & add sports bar
But i noticed some rusty part beneath the hilux, is it normal for hilux?