B-grade - can be returned as faulty product, repaired and put back to sale!
sometimes people return product, but it's not even damaged..
If you buy for example b-grade laptop, u can find wear/scratches/etc (because of use of previous user) but hardware is checked/repaired and in fully working order!
as to: "if it has bits missing" you will never know, till you receive a product.
I bought b-grade mobo once, and it was nothin' but mobo, not even original box!
(I think it was worst scenario).
so you should expect missing items/manuals/software cd/etc. ... it's really is "how lucky u r"
as in stock can be 10 same items which are sold as b-grade, one can be as brand new, with everything inside...and other returned as damaged, repaired and with empty box!
what d'you want to buy?
Thanks