That looks dyesublimated, right? It's amazing how well the keys have held up over the years. It's good to know that under normal house-use conditions, these expensive keysets we buy can outlive us 
That Desko has mixed PBT and ABS keycaps on it. The dye sub keycaps are the RGB Control/Alt/Shift, and the pipe slash |\, +=, {[, }],. :;, "", and Tilde ~ keys. The other keycaps are all ABS thick double shots. They might be quite nice, depending on the level of shine.