Erlensee

Just a quick question. I have a XJ900F (on an E-plate - 1987) which I use as a work hack (great bike btw) Did Yamaha at any time (for the UK Market) have ventilated discs front and rear or just rear .... I ask as some plum on the bay of e has sent thru' 2 rear vented discs claiming they are from the front. So before I let lose on him, I thought I'd post and ask the question here ... Thanks for looking btw ..... Cheers Richard (Southampton UK)