They are standard R8 collet tool holders. Interesting to see 4 different size R8 annular cutters each on their own shank. The annular cutters I have purchased in the past for my old MT3 mill/drill were all individual Welden cutters that can be installed on a universal Welden shank. I recently bought a Welden R8 shank so I could use the cutters on my Hartford Bridgeport Clone.
There is also an adjustable R8 Boring Head there.
If everything is still sharp and not abused, I think it's probably a reasonable (but not great) deal.