There's a huge difference between the two. A tonal center is the note your harmony and melody will sound at home at; while guide tones are the notes that not only greatly define the harmony at that point, but also typically help lead from the current chord to the following chord.
Think of it this way. In a typical ii7 - V7 - I7 in C major, C is the tonal center throughout the progression. The guide tones however change based on the chord, and by default, are the 3rd and 7th of a 7th chord so in this case those guide tones would be F and C for Dm7, B and F for G7, and E and B for CMaj7. As you can see, from these notes we create a nice chromatic line of F-F-E and C-B-B for the individual guide tones which can greatly be taken advantage of in voice leading the progression.