Thank you for the reply. I did not send the pictures to Dillon, but I did send them an email and this is their response.
It is not necessary to upgrade your 450 to a 550. You can load 223 and 308s on the RL450.
As is, you need dies and caliber conversion kits:
223 conversion kit #20128
308 conversion kit #20130
223 die set #10839
308 die set #15574
Case lube #13733
Thank you,
Dillon Precision Products, Inc.