Yes, when using Fusion 1. Compatt 6+ will respond to Wideband 2 commands and will operate using Wideband 2 ranging.
Therefore it will behave exactly as a standard Compatt 6 when used with Fusion 1 in Wideband 2 mode in a standard Compatt 6 array. Note that Wideband 1 is not supported by default in Compatt 6+. If Wideband 1 is required, you can install legacy Compatt 6 firmware in Compatt6+. Fusion 2 users need to use Compatt 6+.