Easy Setup Question

if the 5 LNB is the old style then yes you will. Go into menu/setup/system setup/satellite then rerun satellite setup. Select slimline 5 LNB. When you go home you'll have to rerun it again
The other issue is the SWM doesnt need the BBC converters and the slimline 5 does. Without these you wont get any HD channels. You can buy them on Ebay for cheap ($5-$10 bucks). You'll need 2 of them (for each tuner)
Another issue is you'll need 2 lines from the LNB to the HR24 as the old system needs one line per tuner