Kubota also sells it but they have their own part number for it. IIRC, 70000-73763, or if you like gray color, 70000-73764.
It'd be wise to double check those part numbers as I'm just shooting from the hip.
Having used plenty of 1208, it's about the same as those two I listed. Actually I prefer to use permatex ultra-grey sealant as it hardens better and paints over easier. I tend to paint the joints after a repair...makes a more professional appearing job. Problem is, though, sometimes people will throw a fit that I "charged them a thousand dollars+ and never did anything to it". I did it, but after painting the joints, an untrained eye can't tell.