The bushings could probably withstand the heat, but that's not the real problem. Before you powdercoat anything you have to make sure it its free of ALL contaminants - grease, dirt or anything else.
So its best to remove everything from the swingarm, degrease it, blast it (mask the areas not to be blasted with painters tape and avoid that area as much as possible), remove the tape, blow it off with air, wash it down with either acetone or denatured alcohol. Then preheat the part to a few degrees higher than you powder says to cure at. Use an IR temp gun to make sure the part (not just the oven) reaches temp.
If nothing ugly rises to the surface of the part during the preheat, let it cool, wash it with acetone again. Use tape to mask off the parts mentioned above not to be powdercoated. I use blue painters tape but there are specific high temp tapes made for powdercoating. I use the blue tape because it sticks better and is cheaper. However it won't stand up to the temps for very long. Not that it matters anyway because as soon as you see the powdercoat gloss over you have to stick your hands in the oven and remove the tape. Any tape left on during the full process is tough to remove after a full cure.
Also it's money well spent to get some silicone plugs and caps to cover up threaded holes and other parts you don't want coated. They work really well and don't have to be removed until after the curing process.
Hope that makes sense and helps.
Check out this forum if you haven't already:
http://forum.caswellplating.com/powder-coating-questions/And here's my gallery. I have a lot more pc'ed parts I need to add.
http://gallery.sohc4.net/main.php?g2_itemId=306724Let me know if you have any pc questions.
Matt