I disconnected the throttle body from the intake plenum 2-3 weeks ago when I changed the spark plugs, I can't remember seeing coolant hoses.
If there are coolant hoses then you're right, you should bleed the coolant system afterwards, no need for a full coolant service IMO unless required.
I didn't change the gasket between the TB and plenum (forgot to buy it), but it still makes a very good seal.