That's a pretty good price. Be aware that to need to drop the bull gear to pull that bull pinion assembly out if you're not aware of that. Note the notch in the bull pinion bearing cage. Also only remove one side at a time because the internal gears can drop.
For any parts you may need, open this link to the Case/IH online parts book for the 606.
International Gas Tractor | Case IH | MyCNH US Store Scroll down to see brakes and select. Hopefully the bearing is OK, they are outrageous through Case/IH. You can copy and paste the part number to NAPA and they usually cross to the national part number. One you get that part number copy and paste that to Google, or Ebay. I bought sets of bearings on ebay from a seller called Patriot Bearing Supply:
Security Measure | eBay All NOS U.S.A Timken bearings for 1/4 to 1/3 the price at Case IH. If it's not in his listing send him a message, he has thousands of bearings not listed. Normally has free shipping too, great guy to deal with.
If you replace the seal without removing the back plate, here's a tip when installing new seal without inverting the seal lip on the splined shaft.
Wrap the shaft with electrical tape starting on the smooth part just outside where the seal rides and wrap outward the full length of the shaft and leave a 1" tail beyond the shaft. Oil the tape, then slide the seal over it, turning it slightly as you push it on, sorta like following threads on a bolt the same direction the tape is wrapped. Being the tape is wrapped from the inside out there are no sharp edges for the seal lip to catch on, it rather jumps over the edges of the tape. When the seal is in place, grab the tail of the tape at the end of the shaft and spiral it off. I've used this method numerous times and have never rolled a lip on a seal. I learned this method 20 years ago from an old Massey-Ferguson mechanic either here on this forum, or another I frequent often. So simple, not sure why I didn't think of it at the time.