That looks very similar to a Durst carrier, Durst blackened the beveled edges at the factory on the glass inserts I have. Those glass inserts look a little too thick as well, they should just be a tiny bit proud of the metal frame. You could make an aluminum insert for a glassless carrier, I did that with 1.5mm thick aluminum sheet for both the lower and upper glasses on the D659 enlarger. File out the hole to match your negative image area. The D606 and others use the same 1.5mm glass inserts.