First: I have the part numbers but I did not install the parts where they were supposed to go because they didn't fit or did not protect.
K7591-91860 and K7591-91870 (Front right and left)
K7591-91710 and K7591-91720 (Rear right and left - these are more like tabs, they don't protect if you mount them on front of rear axle but they do provide some protection on the rear side of rear axle. Because I wound up using these on the rear of the rear axle instead of the front as Kubota called for, I ordered another set off EBAY. See below.
I also ordered another set of the 91860 and 91710 off EBAY because I wanted to do front AND rear of rear axle. I use the RTV for bush hogging and trail clearing so it sees some rough service sometimes.
The bolts you need are Kubota part 0127-50625, two per guard. The cross reference to Hillman 08235-7-1049-6, available at Lowes (M6-1.00x30)
What I wound up with was:
Factory installed CV guards on front of front axle. No protection on rear of front axle.
Kubota CV guards on front of rear axle and tabs on the rear of the rear axle.
Pictures (last six numbers of jpg)
133615 - Front, passenger side, outer CV
133628 - Front, driver side, outer CV
133710 - Front, driver side, inner CV (wanted to show you it has no guard but in far enough inboard that it doesn't take a lot of abuse)
133934 - Rear, passenger side, outer CV, FRONT side of rear axle
133821 - Rear, passenger side, outer CV, REAR of rear axle (these are the guards that are more like tabs. Useless for the front as Kubota calls for but provides some protection for the back of the rear axle.)
List price for each guard is around $16 (list price) and you can negotiate a better price and I did better on EBAY. The bolts from dealer are about $1.30 each. Lowes $2.40 for four bolts.
I hope this helps you. I wanted to fabricate my own but no time and no equipment.
Ohio Pawpaw Grower