I see enough bleeding around the edges of the colored sections to be pretty sure the colors were added with glass paints or stains !! Some of the blue runs into the clear and the edges are not straight as they should be if colored when it was molded !! This technique would be almost impossible to do on pressed glass !! If it were original to the piece there would be more out there somewhere and I found no record of anything similar having been made !! They would not have made only one !!
The person I emailed is MIA !! But I heard her husband is running for a senate seat so she is likely helping with that !!
You can try taking a small knife or anything sharp and scratch an area where it is outside the lines to see if it is clear under the colors !!
The glass paints are fired on in a home oven !!