If you mean materials like focus crystals, sulphur, anomolous bulk scan data etc. then yes, absolutely. What you won't get in Horizons is the on-foot stuff like circuit switches, SDP's * and compact libraries.
* Some would argue these aren't present in Odyssey either...
I only go into Horizons when I need to solve a "separated from my ship" issue that cannot be resolved in Ody. Doesn't happen very often but it does still happen. I think the last time was on my carrier and my ship was still in space and I couldn't transfer it nor could I choose another ship...There may have also been a server disconnect involved that created the problem in the first place.
Thanks guys for the reply...
I'm finished filling up the Carrier cargo with Tritium, gonna depart for another exploration soon. Information will be very useful I guess weaapons will still need Synthesis in Odyssey...