Jay,
I think all of the solid wood drawer boxes are 5/8\" with a choice of a 1/4\" or 3/8\" bottom.
The plywood boxes are 1/2\" sides.
Someone can correct me if I am wrong.
Kerry
I checked at Conestoga's website, and it appears that you're right. Their solid wood drawer boxes use 5/8\" material for the sides.
I have dealt with Conestoga off and on for years, and they used to have other options for drawer sides, and since it's not spec'd out on the Member store site, I wasn't sure what the actual material is.
Material thickness makes a big difference with drawer slides like Blum Tandem.