Your best bet is to go to the Vendor/Mfr you want to use and see if they have information regarding your specific Slip-Ons. There are some that will work, but may require slight modifications to the heat-shields or similar minor mods.
I asked this on the exhaust section but didn't get a response. Does anyone know if earlier slip-ons will fit a 09 ultra?
Some will! It seems the problems are with the wider wheel/tire/swingarm cause the rear axle nut to interfere with some of the larger diameter slip ons. One of the best will fit, Rhinehart slipons will fit according to the Bub Enterprises web site. I guess the smaller diameter works to their advantage. I did see a streetglide at the HD shop last Saturday that had a set of V&H Basic slipons on it but it had not been ridden yet the up and down movement may damage them because V&H says they won't work.