MT, TNE, and T4 used the same trade system as Bk7.
T20 uses a modified/expanded version of Bk2.
T5 is related to and derived from Bk 7, but not the same.
GT core is its own thing.
GTFT is a different thing again, but procedurally similar to GT.
GTIW hybridizes GTFT and Bk2...
HT uses a close derivative of Bk2; it's further than T20, but still obviously derived from Bk2.
MGT uses a unique system, as well, but it incorporates some ideas from Bk7 and T20; the special credit in MGT1 is because I dumped all my price research at Gareth upon his request...
CT-77 and CT-81 both use the same Bk 2 trade system, but the rules for how many lots are available for freight and how many passengers are available are quite different.
CT-83 (aka TTB) and CT-84 (ST) use the same as CT-81.
Note that, in CT, using CT-77 or CT-81 will affect profitability due to different operational cost regimes, no matter which trade system you use with it.