Royal Metal Co Mid Century chairs

Just picked up these awesome Mid-Century Royal Metal Co. Chairs from a local thrift store. I know that they have value, but I am unsure on what that is. I had difficulty finding any sale records of the chairs or an approximate manufacturing date. I found a similar set of 4 in a robins egg blue color for $1450 on 1stdibs.com. These chairs have minor damage to the vinyl and overall appear to be in fine condition. Also, along with the Royal Metal emblem on the underside both have the original tag from the manufacturer stating the materials used in the construction of the chair. Below the materials is a spot for a delivery date which is left blank on both chairs. As an added funky factor to the chairs they are both stamped with a "Amercan Hospital Chair" label. So I assume they were used in a medical facility. I am just interested in more information on the chairs as well as a ballpark value if possible.