German Sideboard Early 20th Century

This Sideboard belonged to my Grandparents since the end of WW2. It was brought here to the USA from Heidelberg Germany around 15 years ago. I distinclty remember this furniture while visiting Germany in the 1970's and 80's, and have seen family photos much older with the furniture in them. From appraisals on another piece (China Buffet) of the same manufacturer, it pre-dates WW2 in it's making. It is in very good condition for it's age. It has 3 large doors, 2 with shelves, and one with drawers. Has a black glass slide out board for cutting? Very heavy piece, that appears to be designed to be taken apart by the looks of some of the hardware. I am looking for what would be it's current market value, as well as the possible Makers of these pieces, which I have been unable to find. I believe the Makers mark is on the backside of all 5 of the drawers (shown in one of the pictures).