Yes. blowdown and seam volume are backwards TMCC compatible commands. Yes, legacy gives you more (quilling whistle) but again, honestly, you get most of the functions under TMCC. This was early visionline, so it's not as legacy centric requiring AUX3 or other commands only under legacy.
The manual
https://www.lionelsupport.com/...17611154PensyCC2.pdf
Page 22 begins the coverage TMCC operations and features
Again, yes, Legacy has more features, but for the most part- the party tricks like whistle steam, swinging bell work just fine under TMCC.