I,m gonna say no. They have totally different mounting systems. The 2014-up T bird LT seat is ultra comfortable, but won't fit my 2013. Don't know if it will fit the Rocket but doubtful.
Of course, you can probably rework the bike to fit the seat, but it seems non-trivial and you'd have to be fine with taking an angle grinder and a welder to it... (but I haven't seen the mounting system on the Thunderbirds so who knows).