My list shows a Gates 39343 as a 6814836AA, or a Dayco 132056, bearing NSK 6203DUM ............. just from cats not first hand ...
My Spanner Guru always said when one idler needs replacing, do the whole lot along with belt, once visited no need to revisit......
I have found most greased parts especially wheel bearings always seem to be alight smear of grease, of course too much is just as bad
Certainly an adventure, I have found once an alloy cast heads get chewed thats it, stuffed forever and end up with similar solution, my tools for such an operation on bastard bits like that.